Partex Denim_Israfil Alam Rana

Department of Textile Engineering

Industrial Attachment

PARTEX DENIM LTD. Banglabazar, Gazipur, Bangladesh

PARTEX DENIM LTD. Banglabazar, Gazipur

Internship: May 20, 2011 to August 20, 2011

Prepared by:

Mohammad Israfil Alam Shift Engineer (Weaving) PARTEX DENIM LIMITED

E-mail: [email protected] Cell: 01717123339

Supervising Faculty:

Professor Syed Fakhrul Hassan

Chairman Department of Textile Engineering

Southeast University Banani, Dhaka

Cell No.: 01711-698261

Industrial Supervisor:

Mr. Zainul Abedin Bhuyan Joy

A.G.M (Weaving) Partex Denim Ltd.

Banglabazar, Joydevpur, Gazipur

PARTEX DENIM

Pag

e 4

Table of Contents Acknowledgement ..................................................................................................................................................... 10

Introduction .................................................................................................................................................................. 11

Company Profile .......................................................................................................................................................... 12

1.1 PARTEX HOLDINGS: .......................................................................................................................................... 13

1.2 Enterprises of Partex Holdings: ....................................................................................................................... 14

1.3 PARTEX DENIM LTD: ......................................................................................................................................... 15

1.4 Work-Time Schedule of the Factory: .............................................................................................................. 15

1.5 Satellite View: ................................................................................................................................................... 17

1.6 Factory Layout: ................................................................................................................................................. 18

1.7 Company Organogram: .................................................................................................................................... 21

Process Flow .................................................................................................................................................................. 22

2.1 Process Flow Chart ........................................................................................................................................... 23

Yarn Store ...................................................................................................................................................................... 24

3.1 Types of yarn used: .......................................................................................................................................... 25

3.2 Yarn count used: ............................................................................................................................................... 25

3.3 Supplier of the Yarn:......................................................................................................................................... 25

3.4 Yarn Store Layout: ............................................................................................................................................ 26

Warping ........................................................................................................................................................................... 27

4.1 Definition: ......................................................................................................................................................... 28

4.2 Objects of Warping:.......................................................................................................................................... 28

4.3 Importance of Warping: ................................................................................................................................... 28

4.4 Types of Warping:............................................................................................................................................. 28

4.4.1 Direct Warping: ....................................................................................................................................... 29

4.4.2 Indirect or Sectional Warping:................................................................................................................ 29

4.4.3 Ball Warping: ........................................................................................................................................... 30

4.4.4 Draw Warping:......................................................................................................................................... 30

4.5 Difference between High speed warping and Sectional warping: ................................................................ 30

4.6 Warping in Partex Denim: ................................................................................................................................ 31

4.6.1 Machine Specifications: .......................................................................................................................... 31

4.6.2 Warping Section Layout: ......................................................................................................................... 32

4.6.3 Machine Main Parts: ............................................................................................................................... 33

4.6.4 Functions of Different Parts: .................................................................................................................. 33

4.7 Briefly Description of Different Parts: ............................................................................................................. 34

4.7.1 Creel: ........................................................................................................................................................ 34

4.7.2 Comparison between H creel & V creel:................................................................................................ 34

4.7.3 Rods: ......................................................................................................................................................... 35

PARTEX DENIM

Pag

e 5

4.7.4 Chain system:........................................................................................................................................... 35

4.7.5 Control Devices: ...................................................................................................................................... 35

4.7.6 Headstock: ............................................................................................................................................... 35

4.7.7 Dust and Fly Accumulation Unit: ............................................................................................................ 37

4.7.8 Warping Plan: .......................................................................................................................................... 37

4.7.9 Warping Procedure: ................................................................................................................................ 37

4.7.10 Count wise Drum Pressure: .................................................................................................................... 38

4.8 Calculations: ...................................................................................................................................................... 38

Dyeing & Sizing ............................................................................................................................................................ 41

5.1 Definition: ......................................................................................................................................................... 42

5.2 Objects of Dyeing: ............................................................................................................................................ 42

5.3 Theory of Dyeing: ............................................................................................................................................. 42

5.4 Denim Dyeing: .................................................................................................................................................. 42

5.5 Dyes use for Denim: ......................................................................................................................................... 43

5.5.1 Vat Dyes: .................................................................................................................................................. 43

5.5.2 Sulphur Dyes: ........................................................................................................................................... 45

5.6 Denim Dyeing Process: ..................................................................................................................................... 47

5.6.1 Rope Dyeing: ............................................................................................................................................ 47

5.6.2 Slasher Dyeing: ........................................................................................................................................ 49

5.6.3 Loop Dyeing: ............................................................................................................................................ 50

5.7 Difference between Slasher and Rope Dyeing: .............................................................................................. 50

5.8 Sizing:................................................................................................................................................................. 51

5.8.1 Definition: ................................................................................................................................................ 51

5.8.2 Objects of Sizing: ..................................................................................................................................... 51

5.8.3 Changes in Yarn due to Sizing: ............................................................................................................... 52

5.8.4 Why Sizing is called Heart of Weaving? ................................................................................................. 52

5.8.5 Techniques of Sizing: ............................................................................................................................... 52

5.8.6 Types of sizing according to application: ............................................................................................... 53

5.8.7 Size Ingredients and their function: ....................................................................................................... 53

5.9 Dyeing & Sizing in Partex Denim: .................................................................................................................... 56

5.10 Machine Specification: ..................................................................................................................................... 57

5.10.1 Creel section: ........................................................................................................................................... 59

5.10.2 Benlink: .................................................................................................................................................... 60

5.10.3 Accumulator: ........................................................................................................................................... 60

5.10.4 Pre treatment: ......................................................................................................................................... 61

5.10.5 Pre-Washing (1-3 box): ........................................................................................................................... 62

5.10.6 Dyeing: ..................................................................................................................................................... 63

PARTEX DENIM

Pag

e 6

5.10.7 Drying Zone:............................................................................................................................................. 69

5.10.8 Accumulator: ........................................................................................................................................... 69

5.10.9 Sizing: ....................................................................................................................................................... 69

5.10.10 Size Cooking Process: ......................................................................................................................... 70

5.10.11 Drying Zone: ........................................................................................................................................ 72

5.10.12 Accumulator: ....................................................................................................................................... 72

5.10.13 Leasing Zone: ...................................................................................................................................... 72

5.10.14 Expansion Comb: ................................................................................................................................ 72

5.10.15 Beaming:.............................................................................................................................................. 72

5.10.16 Transportation of Beams: .................................................................................................................. 72

5.11 Functions of chemicals used in Yarn dyeing: .................................................................................................. 73

5.12 Equipments used in dyeing lab:....................................................................................................................... 74

5.13 Chemicals used for dyeing and sizing: ............................................................................................................ 75

5.14 Calculation: ....................................................................................................................................................... 76

Weaving ........................................................................................................................................................................... 77

6.1 Definition: ......................................................................................................................................................... 78

6.2 Basic Weave Designs: ....................................................................................................................................... 78

6.2.1 Plain Weave: ............................................................................................................................................ 78

6.2.2 Twill Weave: ............................................................................................................................................ 79

6.3 Classification of Modern Weaving Machines: ................................................................................................ 79

6.3.1 Air-Jet Weaving: ...................................................................................................................................... 80

6.3.2 Rapier Weaving: ...................................................................................................................................... 80

6.3.3 Projectile Weaving: ................................................................................................................................. 81

6.3.4 Water-Jet Weaving:................................................................................................................................. 81

6.4 Weaving in Partex Denim: ............................................................................................................................... 81

6.4.1 Specification of Airjet: ............................................................................................................................. 82

6.4.2 Specification of Rapier: ........................................................................................................................... 82

6.5 Looming:............................................................................................................................................................ 83

6.6 Drawing-In:........................................................................................................................................................ 83

6.7 Tying-In:............................................................................................................................................................. 83

6.8 Basic Motion: .................................................................................................................................................... 83

6.8.1 Primary Motions: ..................................................................................................................................... 84

6.8.2 Secondary Mechanisms: ......................................................................................................................... 92

6.8.3 Tertiary Mechanisms: ............................................................................................................................. 93

6.9 Special Features of PICANOL: .......................................................................................................................... 94

6.9.1 Unique Sumo main motor: ..................................................................................................................... 94

6.9.2 Picanol PC Suite: ...................................................................................................................................... 94

PARTEX DENIM

Pag

e 7

6.9.3 Automatic full pick finding:..................................................................................................................... 95

6.9.4 Exchangeable shed formation: ............................................................................................................... 95

6.9.5 Electronic Let-Off and Take-Up: ............................................................................................................. 95

6.9.6 Easy fitting and removal of warp beam and cloth roll: ........................................................................ 95

6.9.7 Perfect lubrication:.................................................................................................................................. 95

6.9.8 Double pressure roller: ........................................................................................................................... 95

6.9.9 Optimized sley drive: .............................................................................................................................. 96

6.9.10 Electronic Selvedge System and Electronic Rotary Leno: ..................................................................... 96

6.9.11 Quick Step filling presenter (Rapier): ..................................................................................................... 96

6.9.12 CANplus prewinders (Airjet): .................................................................................................................. 96

6.9.13 Programmable Filling Tensioner (Airjet):............................................................................................... 96

6.9.14 Clamp on the movable main nozzle (Airjet): ......................................................................................... 96

6.9.15 Argus filling detector (Airjet): ................................................................................................................. 97

6.9.16 Fixed and movable main nozzles (Airjet): .............................................................................................. 97

6.9.17 New relay nozzles and valves (Airjet): ................................................................................................... 97

6.9.18 Adaptive Relay Valve Drive (Airjet): ....................................................................................................... 97

6.9.19 Stretch nozzle (Airjet): ............................................................................................................................ 98

6.10 Different Parts Manufacturers Name: ............................................................................................................ 98

6.11 Selvedge: ........................................................................................................................................................... 99

6.12 Calculation: ..................................................................................................................................................... 100

Finishing........................................................................................................................................................................ 102

7.1 Definition: ....................................................................................................................................................... 103

7.2 Objects of Finishing: ....................................................................................................................................... 103

7.3 Types of finishing: ........................................................................................................................................... 103

7.3.1 Physical/Mechanical Finishing: ............................................................................................................ 103

7.3.2 Chemical Finishing:................................................................................................................................ 103

7.4 Finishing In Partex Denim: ............................................................................................................................. 104

7.5 Process Sequence of Denim Finish Line: ....................................................................................................... 106

7.5.1 Brushing: ................................................................................................................................................ 106

7.5.2 J-Box: ...................................................................................................................................................... 106

7.5.3 Singeing: ................................................................................................................................................. 106

7.5.4 Softening: ............................................................................................................................................... 109

7.5.5 Skewness Control: ................................................................................................................................. 109

7.5.6 Dryer:...................................................................................................................................................... 112

7.5.7 Stenter: .................................................................................................................................................. 112

7.5.8 Sanforizing: ............................................................................................................................................ 112

7.5.9 Calendaring: ........................................................................................................................................... 114

PARTEX DENIM

Pag

e 8

7.6 Mercerization: ................................................................................................................................................ 115

7.6.1 Physio-chemical changes during mercerization:................................................................................. 116

7.6.2 Advantages of mercerization: .............................................................................................................. 116

7.6.3 Effect of mercerizing condition: ........................................................................................................... 116

7.7 Desizing: .......................................................................................................................................................... 117

7.8 Resin Finishing: ............................................................................................................................................... 118

Inspection ..................................................................................................................................................................... 119

8.1 Inspection in Partex Denim:........................................................................................................................... 120

8.2 Inspection Process: ......................................................................................................................................... 120

8.3 Four (4) Point System: .................................................................................................................................... 120

8.4 Machinery Description: .................................................................................................................................. 121

8.5 Major Fabric Faults: ........................................................................................................................................ 123

8.6 Quality Assurance Procedure: ....................................................................................................................... 126

Research & Development ...................................................................................................................................... 127

9.1 R & D Department in Partex Denim: ............................................................................................................. 128

9.2 Developed Samples: ....................................................................................................................................... 129

9.3 Name of some Buyers: ................................................................................................................................... 131

Denim Wash ................................................................................................................................................................. 132

10.1 Denim Washing: ............................................................................................................................................. 133

10.2 Types of Denim Wash: ................................................................................................................................... 134

10.2.1 Desizing: ................................................................................................................................................. 136

10.2.2 Bleaching:............................................................................................................................................... 137

10.2.3 Stone wash: ........................................................................................................................................... 138

10.2.4 Enzyme wash: ........................................................................................................................................ 140

10.2.5 Sand Blasting: ........................................................................................................................................ 141

10.2.6 Acid wash: .............................................................................................................................................. 141

10.3 Denim Washing in Partex Denim:.................................................................................................................. 143

10.4 Chemical Used for Washing: .......................................................................................................................... 144

10.5 Machine used in washing unit: ...................................................................................................................... 145

10.6 Most Common Denim Washes: ..................................................................................................................... 147

Utilities .......................................................................................................................................................................... 153

11.1 Definition: ....................................................................................................................................................... 154

11.1.1 Water Supply: ........................................................................................................................................ 154

11.1.2 Boiler: ..................................................................................................................................................... 155

11.1.3 Generator: ............................................................................................................................................. 156

11.1.4 Air Compressor: ..................................................................................................................................... 157

11.1.5 Chiller: .................................................................................................................................................... 160

PARTEX DENIM

Pag

e 9

11.1.6 Humidification Plant: ............................................................................................................................ 162

Effluent Treatment Plant ................................................................................................................................. 163

Process Flow Chart: ................................................................................................................................................. 166

11.2 Pre-Treatment ................................................................................................................................................ 167

11.3 Primary-Treatment ......................................................................................................................................... 167

11.4 Secondary-Treatment .................................................................................................................................... 168

Maintenance ................................................................................................................................................................. 171

12.1 Introduction: ................................................................................................................................................... 172

12.2 Types of Maintenance:................................................................................................................................... 172

12.2.1 Reactive/Break-down Maintenance: ................................................................................................... 172

12.2.2 Preventive/Schedule Maintenance:..................................................................................................... 173

12.2.3 Predictive/Planned Maintenance: ....................................................................................................... 173

12.2.4 Capital Replacement: ............................................................................................................................ 174

12.3 Functions/Elements of Maintenance Department: ..................................................................................... 175

12.4 Requirements for Good Maintenance: ......................................................................................................... 176

Store & Inventory Control ................................................................................................................................... 177

Marketing Activities................................................................................................................................................ 180

Security ......................................................................................................................................................................... 183

Quality Assurance..................................................................................................................................................... 186

Discussion ..................................................................................................................................................................... 192

Conclusion .................................................................................................................................................................... 193

References: ................................................................................................................................................................... 194

PARTEX DENIM

Md. Israfil Alam Rana [email protected] Cell: 01717123339

Pag

e 10

Acknowledgement

Firstly I would like to thank the Almighty Allah for giving me patience to conclude my internship program

& finally this industrial attachment.

Preparing the internship report based on “Fabric Manufacturing Technology (Denim)”, I have

understood that it is very difficult to find out the basic and fundamental aspects of fabric manufacturing

are largely distant from the theoretical bookish knowledge.

I express my heartfelt gratitude to Mr. M. S. Hasan, General Manager, Partex DenimLtd. for giving me

permission for industrial training in his mill.

I am also thankful to Mr. ZainulAbedinBhuyan, A. G. M. (Weaving), for his cordial support during the

period of internship.

After him I would like to thank Mr. Rafat Bin Hasan for his guideline and endless help. My gathered

knowledge about denim washing will not successful without his help.

From Preparatory Section I would like to thank Mr. Alamgir (Warping), Mr. Akash (Warping), Mr. Aziz

(Dyeing) for their guideline about Warping, Dyeing & Sizing process.

From Weaving Section I would like to thank Mr. Radhakanta Paul (Manager) & Mr. Sukanta Kumar (Asst.

manager) for their support. They helped me a lot about learning weaving process both airjet and rapier

loom.

I would like to thank Mr. MahfuzurRahman (Manager) from finishing section, Mr. Masud& Mr. Kaium

from R&D department. I have learned so many things form R&D department. Without their help it will

difficult for me to understanding the whole process. Special Thanks to Mr. Mogh (A.G.M) from utility

section. I have learned so many things in this section specially ETP.

I am very grateful and deeply indebted to our respected teacher Professor Syed Fakhrul Hassan,

Chairman, Department of Textile Engineering, Southeast University for his continuous support,

encouragement, suggestion, guidance and constructive criticism to get through the industrial training.

I thank to the management of Partex Denim Ltd. for giving me the opportunity to undergo Industrial

Training there.

Thus all in all it can be said that without their help it would not be possible for me to prepare this

internship report. So I would like to convey thanks notation to all who directly or indirectly contributed

and inspired me to time to time in preparing the report.

My gratitude also goes to all the employees of Partex Denim Ltd. for their sincere co-operation, support

and valuable advice which they have provided me during the training period.

PARTEX DENIM


Pag

e 11

Introduction

If the theoretical knowledge is a glass of water then the practical knowledge would be drinking of water.

It is always very easy to make a man understand about a firebox by showing and lighting practically

rather than describing theoretically who has not ever seen a firebox. So, for any technical education the

practical experience is the most important as well as the theoretical knowledge.

As we are studying in a technical line, it is always important for us to gather the practical knowledge.

Through our study life the only biggest chance for us to combine the theoretical knowledge with the

practical knowledge is the “Industrial Attachment Period” that comes only once in the education life

when completing under graduate education. So we can easily realize the importance of Industrial

Attachment. And in addition the knowledge we gathered from the industrial training reflects in the

report of industrial attachment note book.

So industrial attachment is the process where a trainee can blend his theoretical knowledge with

practical knowledge which increased the ability of work, skills, performance and attitude and so on. It

also provides sufficient knowledge about production management, productivity evaluation, work study

& efficiency, industrial management, production planning and control, production cost analysis,

inventory management, utility, maintenance and so on. Industrial attachment makes us reliable to be

accustomed with the industrial atmosphere and also improve courage and inspiration to take self-

responsibility.

I have tried to my best to prepare this note book applying our best efforts. I have tried to gather all the

necessary information to make it a valuable for me as well as for everyone. I think it will help me a lot in

future practical life.

PARTEX DENIM


Pag

e 12

Chapter One

Company Profile

PARTEX DENIM


Pag

e 13

1.1 PARTEX HOLDINGS: Partex Holdings is a conglomerate comprising 20 companies across diverse industries. Adjusting to the

ever changing global environment, it is an exodus from patrimonial management system to professional

management system, using the Partex name as a springboard that has been respected in Bangladesh for

50 years for its adherence to strong values and business ethics.

Founded by Mr. M.A. Hashem in 1959, the mother ship PARTEX’S early years were inspired by the spirit

of nationalism. Initially a major importer of consumer products and materials, fast transition to import

substitution made it possible to become pioneer in several industries of national importance in newly

independent Bangladesh. In more recent times, its pioneering spirit has been showcased by PARTEX

HOLDINGS, with direction from the competent next family generation comprising Mr. Aziz Al-Kaiser, Mr.

Aziz Al-Mahmood, Mr. Aziz Al-Masud, Mr. Showkat Aziz Russell & Mr. Rubel Aziz.

PARTEX HOLDINGS companies now operate in business sectors like communications and information

technology, energy, materials, services and consumer products. The major Partex Holdings companies

are Partex Plastics, Partex Denim, Partex Beverage, Amber Pulp, Amber Cotton, Partex Foundry Ltd.,

Partex Rotor Spinning Mills, Partex Spinning Mills, Dhakacom Limited, Partex Sugar Mills Ltd., Partex

Paper Mills Ltd.

We are, by and large, based in Bangladesh and have significant international clients. In tandem with the

increasing international footprint of PARTEX HOLDINGS companies, the Partex flagship is also gaining

international recognition.

In a short span of time, PARTEX HOLDINGS’ concerns have shown incomparable success. Partex

Beverage Ltd. has positioned at the 2nd position in the local beverage market being the sole official

bottler of Royal Crown Cola Co. To cater international demand, Partex Denim has been supplying 3

million yards per month with minimum lead time, superior quality at the best price, color consistency

and meticulous packaging. Our IT services are to cover all 64 districts by end of 2010 through Dhaka

com, which is also connected to all major Telecom Carriers in the country.

Going forward, Partex Holdings is focusing on new technologies and innovation to drive its business in

Bangladesh and internationally. Anchored in Bangladesh and wedded to traditional values and strong

ethics, Partex Holdings companies are building multinational businesses that will achieve growth

through excellence and innovation, while balancing the interests of shareholders, employees and civil

society.

PARTEX DENIM


Pag

e 14

1.2 Enterprises of Partex Holdings:

Textiles

• Partex Rotor Spinning Mills Limited • Partex Spinning Mills Limited

• Partex Rotor Mills Limited

• Amber Cotton Mills Limited • Partex Denim Limited

Food & Beverages

• Partex Sugar Mills Limited • Partex Beverages

Plastics

• uPVC Pipes & Fittings • PP-R Pipes & Fittings • Plastic Furniture • Superware • Accessories

Paper

• Amber Paper & Pulp Mills Limited

Real Estate

• Partex Real Estate Limited

ICT

• DhakaCom Limited • BEPS • Radio Dhaka

Trading

• Partex Trading & Shipping Limited

Agro Business

• Fisheries • Agriculture • Partex Foundry Limited

PARTEX DENIM


Pag

e 15

1.3 PARTEX DENIM LIMITED:

Company Profile

Company Name : PARTEX DENIM LTD.

Company Status : Private

Owner : Mr. M.A.Hashem

Year of Establishment : 2005

Factory Location : Banglabazar, Joydevpur, Gazipur.

Corporate Office : House # 37, Road # 01, Block # 1, Banani

Dhaka-1213,Bangladesh

Web: www.Partexholding.com

Type of Factory : Fabric Manufacturing

Product : Denim Fabric

Annual Production : 22 million yards

Project Cost : 30 million US dollar

Total Area : 30 acres

Structure : Steel structure surrounded by brick wall

Total Employee : 1200(250 executive & officers)

1.4 Work-Time Schedule of the Factory: The Factory Runs 24 Hour A Day. It Maintains A Tight Work Schedule. That Is Shown In The Chart.

Section Number of Shift Duration Warping 2 12 hours each

Dyeing 3 8 hours each Weaving 3 8 hours each

Finishing 2 12 hours each

Utility 3 8 hours each

Security 3 8 hours each

Stuff & Commercial General Shift 9 a.m. – 5 p.m.

Top Management General Shift 9 a.m. – 5 p.m.

PARTEX DENIM


Pag

e16

Bangla Bazar

Rajendrapur Chourasta

National Park

PARTEXDENIMLTD.

Gazipur Chourasta

Dhaka-Mymensingh

Highway

Mirzapur Bazar

Kapasia

Dhaka-T

ongi

Road

Joydebpur Railway Station

Chandra

Factory Location Map

PARTEX DENIM


Pag

e 17

1.5 Satellite View:

ETP Humidification Plant

Yarn Store

Admin Office

Buyer rest house

Main Gate

Fabric Store

Utility

Weaving

Finishing

Garden

Warping

Dyeing & Sizing

Play ground

Entrance Gate

WTP

PARTEX DENIM


Pag

e18

1.6 Factory Layout:

Desizing

Resin Finishing

Mercerizing

Denim Finish Line 2

Denim Finish Line 1

R & D

Dyeing & Sizing Creeling

Dyeing & Sizing Creeling

War

pin

g

Inspection& Packing

Dyeing Lab

A= Front Gate M=Mechanical office B=Mosque T=Toilet C=Sewing section R=Coating chemical store D=Doctor G=Gate E=Electrical office H=Warping & Sizing office F=Finishing office → = Gate S=Spare parts K=Washing unit

W=Weaving office

Rapier loom

Airjet loom

625 feet

34

0 feet

Total Space: 212500 square feet

PARTEX DENIM


Pag

e 19

Partex Denim is a Premium Denim producer. It commenced its production in 2005 with the best and

latest machinery available in the world. The current capacity is two Million yards of Fabric per month.

On the fabric side, our product range includes weights from 4.5 ozs up to 14.5 ozs using multi-count/

multi twist ring/open-end yarn using CAIPO technology. We have two worlds best BenningerSlasher

Indigo dye range from Switzerland and Germany, which are capable of doing colored bottoming/topping

reactive colored denim/Sandwich/plus very deep indigo shades. Weaving is done on machines from

Picanol Belgium.

Most modern Weaving machines both in rapier and airjet version to get good productivity and to make

trouble free fabric even if it is made with coarser slub or spandex. Picanol Omniplus 800 and GamMax

rapier from Belgium where used some special device as per our requirement which can help to produce

better fabric than others mill though they used also same machine. The loom shed is totally humidified

and temperature controlled with enough air circulation and sufficient pressure to help machine and yarn

to make better fabric and always make the shed clean.

On the finishing side, we have Cibitex which is the most modern finishing range introduced in

Bangladesh for the first time by Partex. It has mini Stenter to keep fabric width same without any

variation. Sufficient brushing, singeing in both side, high quality skew device, bigger padder, sanforizer

and compacting device to make the fabric more clean and maintain shrinkage properly. Partex was the

pioneer of starting Flat finish fabric commercially in Bangladesh and is capable of doing a variation in the

Figure: Front View of Partex Denim Ltd.

Figure: Weaving Section Figure: Dyeing Section

PARTEX DENIM


Pag

e 20

flat quality as per the buyers requirement. They can make Soft Finish, Flat Finish and Super Flat as well.

This machine was specially designed as per Partex’s requirement. Partex gives importance to inspection

machines also. To control proper tension and easy handling. Partex uses most modern machines with

conveyer belt with auto wrapping and packing.

On the quality side, Partex uses most modern and efficient lab instruments from Atlas UK which is

operated by trained technicians. The variable light box, Spectrophotometer, Rubbing tester, Washing

Fastness, Tensile strength tester etc. gives accurate results and helps to keep quality good and more

consistent.

On the development side, the R&D department is independent and equipped to promptly invent new

designs for new fashion and develop buyer’s requirements timely. This department keeps all documents

from dyeing recipe to fabric construction and keeps master roll to keep shade in same consistent even

over a longer discontinuity. Partex always researches to develop new fashion as per the world

requirement as well as to maintain comfort & durability.

Partex is manufacturing all kinds of denim fabrics in rigid and stretch in the following versions: Non flat,

Flat Super flat, Resin coated, Pigment coated, Over Dyed, PU coated, ECRU denim, RFD denim, Ash

colored denim, Reactive colored denim, Color denim. Partex is manufacturing bi-stretch commercially

for the first time in Bangladesh and coming soon with Organic denim fabric. There is no end in fashion.

They are also in the process of making Linen denim, viscose denim and so on.

On the environment side, Partex maintains a state of the art Water and Effluent Treatment Plant

meeting toughest international standards and always looks to make the working environment greener.

It has plenty of lush trees surrounding the plant premises. Partex maintains labor laws, gives all facilities

like medical, housing, leave, festival bonus etc to their employees.

Pacific Jeans, IDS Group, Kenpark Bangladesh Ltd., Liberty Fashion, Standard Group, M&J Group, Tusuka

Trousers, Shanta Denims, ABA Fashions Ltd., Regency Bangladesh Ltd., Jeacon Garments Ltd., Tanaj

Fashion, Windy Apparels Ltd., Swan Garments Ltd., Birds Garments, EPIC Designers, BrandixSrilanka and

many more.

PARTEX DENIM


Pag

e21

1.7 Company Organogram:

Asst. Manager

Shift Engineer

Sr. Production Officer

Production Officer

Asst. Production Officer

Chairman

Managing Director

General Manager

AGM Preparatory & Dyeing

AGM HR & Administration

AGM Utility & Maintenance

Manager Finance & Accounts

AGM Weaving

Manager Civil

Manager Marketing

Manager Commercial

Coordinator Production

& Marketing Maintenance

Manager Preparatory

Manager Dyeing

Manager Finishing

Manager Weaving

Asst. Manager

Shift Engineer


Production Officer


Trainee Officer Trainee Officer

Asst. Manager

Shift Engineer


Production Officer


Trainee Officer

Asst. Manager

Senior Chemist

Chemist

Asst. Chemist

Trainee Chemist

PARTEX DENIM


Pag

e 22

Chapter Two

Process Flow

PARTEX DENIM


Pag

e 23

2.1 Process Flow Chart

For Warp Yarn

Yarn in Cone

Warping

Pre-treatment Indigo Dyeing

Drying Sizing Drying

Beaming

Weaving

Singeing Softening Skewness

Sanforizing Calendaring

Mercerizing Stentering

Desizing

Resin Finishing

Inspection Packing Delivery

Pre

par

ato

ry

Fin

ish

ing

For Weft Yarn

Yarn in Cone

PARTEX DENIM


Pag

e 24

Chapter Three

Yarn Store

PARTEX DENIM


Pag

e 25

3.1 Types of yarn used: Ø Rotor yarn

Ø Ring yarn

Ø Slub yarn

Ø Polyester

Ø Lycra yarn

3.2 Yarn count used: Ø For warp : 6, 7, 8, 9, 10, 12, 14, 16, 20, 30 (Slub + Normal)

Ø For weft : 6, 7, 8, 9, 10, 12, 14, 16, 20, 30 (Slub + Normal)

Ø Polyester : 300D, 600D

Ø Lycra : 10L40D, 16L40D, 200L40D, 300DL40D

3.3 Supplier of the Yarn:

Ø Partex Rotor Mills Ltd.

Ø Partex Rotor Spinning Mills Ltd.

Ø Amber Cotton Mills Ltd.

Ø Mahamud Denim Ltd.

Ø Sapphire Textile Mills Ltd.

Ø Indorma

Ø ShaoxingXingji Import & Export Co. Ltd.

Ø Nishat Mills Ltd.

Ø Ashik Composite Textile Ltd.

Ø Salek Textile

Ø Purbani Rotor Mills

Ø Square Textile Ltd.

Ø Kader Synthetic

PARTEX DENIM


Pag

e26

3.4 Yarn Store Layout:

Total Space: 19950 square feet

175 ft

11

4 ft

Gate

Gate

PARTEX DENIM


Pag

e 27

Chapter Four

Warping

PARTEX DENIM


Pag

e 28

4.1 Definition: In general terms, warping is transferring many yarns from a creel of single-end packages forming a

parallel sheet of yarns wound onto a beam or a section beam.

The warp beam that is installed on weaving machine is called the weaver’s beam. A weaver’s beam can

contain several thousand ends and for different reasons it is rarely produced in one operation.

4.2 Objects of Warping: Ø Construction of warp yarn beam.

Ø Construction of a parallel of yarn shift.

Ø Modifying the faults of yarn like thick and thin places, large knots etc.

Ø Winding the pre-determined length of yarn.

Ø Combination of small packages.

Ø Finding long length of warp yarn.

Ø Accelerating the next process.

4.3 Importance of Warping: Ø The tension of wounds ends must be uniform and possibly constant during all the time of with

drawl from supply package.

Ø Warping should not impair the physical and mechanical properties of yarn.

Ø Pre determined length of warping should be high.

Ø The surface of warping package must be cylindrical.

4.4 Types of Warping: There are four types of warping, which are as follows:

1. Direct Warping

2. Indirect or Sectional Warping

3. Ball Warping

4. Draw Warping

PARTEX DENIM


Pag

e 29

4.4.1 Direct Warping: In direct warping, the yarns are withdrawn from the single-end yarn packages on the creel and directly

wound on a beam.

Direct warping can be used to directly produce the weaver’s beam in a single operation. This is suitable

for strong yarns that do not require sizing and when the number of warps on the warp beam is relatively

small. This is also called direct beaming. It can also be used to make smaller, intermediate beams called

warper’s beams. These smaller beams are combined later at the slashing stage to produce the weaver’s

beam. This process is called beaming.

4.4.2 Indirect or Sectional Warping: In Indirect warping, a section beam is produce first. It is also called band warping or drum warping. The

section beam is tapered at one end. Warp yarn is wound on the beam in sections, starting with the

tapered end of the beam. Each section has multiple ends that are traversed together slowly during

winding along the length of the section to form the angle. Due to the geometry of the yarn sections, the

last section on the beam will have a tapered end that will make the whole yarn on the beam stable. It is

important that each layer on the beam contain the same number of yarns. The same length of yarn is

wound on each section. After all the sections on the beam are wound completely, then the yarn on the

beam is wound on to a regular beam with flanges, before slashing. This process is called re-beaming.

Figure: High speed/Direct warping

Figure: Sectional warping

PARTEX DENIM


Pag

e 30

4.4.3 Ball Warping:

Ball Warping is mainly used in manufacturing of denim

fabrics. The warp yarns are wound on a ball beam in the

form of a tow for indigo dyeing. After the dyeing process,

the tow is separated and wound on a beam. This stage is

also called long chain beaming or re-beaming.

4.4.4 Draw Warping:

Draw Warping is combining the drawing of filament yarns with

heat setting and warping processes to achieve uniform

stretching and heating for improved dye uniformity, end to end.

It is used for weaving of thermoplastic yarns.

4.5 Difference between High speed warping and Sectional warping:

High speed warping Sectional warping

To produce common fabric To produce fancy fabric

High production Low production

Large no of yarn are required Small amount of yarn are required

Weavers beam is produced after sizing Weavers beam is produced before sizing

Creel capacity is greater than 1200 Creel capacity is greater than 300 to 400

Cone, cheese winding are used Flanged bobbin is used

Single yarn is used Twist yarn is used

Cheap process Costly process

Uniform tension Not uniform tension

Used very much Not used

Figure: Draw warping

Figure: Ball warping

PARTEX DENIM


Pag

e 31

4.6 Warping in Partex Denim: The warping section of the Partex Denim Ltd. is working under the A.G.M. of Preparatory Section. AGCH-

9240, UZWIL BENNINGER 2005 warping machine with v-creel is used here. The department is connected

with dyeing section directly and working 24 hrs. R&D department inspects the cones which is converted

in beams of required length and forwarded to dyeing section.

4.6.1 Machine Specifications:

NAME : BEN DIRECT WARPING MACHINE

Total Machine : 02

Model : AG, CH-9240 UZWIL BENINGER 2005

Origin : Germany

Year of Installation : 2005

Creel capacity : Max.: 520, Min.: 372

Winding Speed : Maximum 1200 m/min

Maximum Beam Diameter : 1250 mm

Air Pressure Required : 5-8 bar

Air Consumption : 2.5 – 3 m3/hour

Power : 21-23 KW

Pressure of Drum : 600 daN

Maximum Length of Yarn Can Wind : Around 30000 m

Yarn Count : Both Ring & Open End yarn

PARTEX DENIM


Pag

e32

4.6.2 Warping Section Layout:

Gate Gate

V-Creel

Win

din

g m/c

Dust Chamber

V-Creel

Head Stock Head Stock

PARTEX DENIM


Pa

ge3

3

4.6.3 Machine Main Parts:

Bobbin Stand/ Package Stand

Holder

Balloon Breaker

Creel Section Yarn Tensioner

Stop Motion

Yarn Guide

Cutter

Motor

Control Board

Beam clamping & De-clamping Zone

Machine Section Pressure Roller

Accumulating zone

Comb

Cleanvac Section

4.6.4 Functions of Different Parts:

Winding on

Winding Speed: 350 - 1200 m/ min

Encoder: Measure the surface speed of pressure drum Motor speed gradually reduced with the increase of beam diameter Inverter controls the motor speed

Yarn Parallelization Each yarn is separated by comb

Each dent contains only one yarn Combs are traversed by motor

Cleaning Combs are cleaned by compressed air automatically at a preset interval

Beam Clamping & De -clamping

By motor

Cleanvac Collects the dusts flying in the winding zone

Collects dusts by creating vacuums by suction fan

Accumulator Accumulator is used for storage of yarn when need to unwinding the beam for knot of yarn due to yarn breakage.

PARTEX DENIM


Pa

ge3

4

4.7 Briefly Description of Different Parts:

4.7.1 Creel:

At the creel, the yarn packages are placed. The machine has travelling package V-creels. The max

creel capacity is 520 cones on one end and 560 cones on the other. When one end is on working

then the cones for next lot are installed on inner ends. After the one end’s stock ends then the creel

is moved to other side. Capstan tensioners are installed at the creel. Guide rods are installed at the

creel.

4.7.2 Comparison between H creel & V creel:

H creel V creel Parallel warping is used for sectional warping as

well as for direct warping. V-creel is used for only in direct warping.

Suitable for comparatively low speed warping. Suitable for high speed yarn warping.

Needs proper yarn guides. No need of yarn guide

Provide low tension on whole beam. Provide uniform yarn tension across the whole beam.

No free yarn from creel to the warping machine because proper yarn guides are required.

Free yarn run from creel to the warping machine.

More time consumable because of low speed. Less time consumable.

More space is consumed. Less space is consumed.

In indirect warping, a constant speed drive is generally required to provide approximately

uniform yarn speed on the surface of the beam.

Surface friction drive and variable speed drive is commonly used to attain the uniform yarn

speed.

H-creel has a wide range of package change system. Example: with reversible package, with unrolling draw off, with fixed package frames, with package trucks, with swiveling package

frames.

V-creel has a low range of package change. Example: reversible frames, reversible frames

with automatic knotter, and with travelling package.

Figure: Creel Section

PARTEX DENIM


Pa

ge3

5

4.7.3 Rods:

Steel rods in creel frame for yarn support and guidance also important for yarn tension. Due to their

structure, rotor yarns have special balloon dynamics. Ballooning is three times greater with rotor

yarns than with ring spun yarns and has its maximum elongation in the spaces between package and

tensioner. Two round metal rods with a smooth and friction-resistant surface achieve effective

balloon reduction.

4.7.4 Chain system: Chain system is connected with motor. Use to rotate the creel frame in cone changing process.

There are two sides of frame one is in working and second side is stationary till the filling of new

cones. Proper oil lubrication is maintained in the system.

4.7.5 Control Devices:

Warp yarns are threaded through capstan tensioners and stop motions at the creel. These

tensioners are provided in order to provide necessary tension. When the machine starts running it

remain closed for a little time in order to straightening of yarns. After the machine comes in running

they open automatically to provide tension.

4.7.6 Headstock:

Figure: Control Device

PARTEX DENIM


Pa

ge3

6

At the headstock, the warper’s beam is installed for winding. The beam width is 1800mm. A guide

roller guides the yarns to the warper’s beam. A pressing roller presses the warp sheet on the

warper’s beam for winding with proper tension.

The yarn build-up is determined by the tension of the warp threads and the press roller force.

Uniform thread tension from the middle of the beam to the outside, i.e. from the front to the rear

ends in the creel, must be assured. The press roller must ensure compact winding and absolute

cylindricity.

The first requirement for non-crossed ends is precision thread guidance with minimal free thread

lengths from zigzag comb to beam. It must be possible to match the width of the thread sheet

exactly to the beam width to avoid errors at the flanges.

The presser roll is of hard paper and has strong end rings to prevent damage. The increasing yarn

diameter on the beam forces the press roller back against the resistance of the pre-set pressing

force. Thanks to this indirect pressing action the winding is always perfectly cylindrical. Upon

braking, the press roller is immediately swung away hydraulically. All friction between roll and yarn

is avoided.

Figure: Headstock

Figure: Drum pressure on yarn

PARTEX DENIM


Pa

ge3

7

The standard equipment is intended for back beams with 40° toothed internal taper. The teeth

ensure exact centering as well as non-slip drive and braking. The machine can also be configured to

accommodate journal beams. To avoid rolled-in threads, in the event of a thread break the direct

warper must be able to be stopped in a short distance, even at the highest speeds and with a fully

wound beam. This is performed by hydraulically operated disc brakes mounted to the both sides.

From the creel, the yarns are passed through the expandable zigzag comb. The required warper’s

beam width required can be set with the help of this comb.

Simple insertion of the threads into the comb. The stepped comb is moved apart to simplify laying in

the ends. The lateral alignment of the comb on the beam and the setting to the exact warp width are

motor-driven. The horizontal comb movement guarantees uniform yarn build-up on the beam. The

traverse can be set steplessly. Due to the vertical movement, the life of the comb is increased.

4.7.7 Dust and Fly Accumulation Unit: On Ben Direct, a dust and fly accumulation unit is installed at the headstock, which sucks dust, fluff

and fly and prevent the warper’s beam from them.

4.7.8 Warping Plan: The warper gets the required no of ends and the number of beams from the R&D department and

then he made the warping plan that how to complete that task whether on one creel or on more no.

of creels.

4.7.9 Warping Procedure: The creel stand has maximum capacity of five cones per stand. The yarn from the cones is

unwounded and passes from rod by cross wound, holed by a catcher guided to the tensioning zone

Figure: Break System

Figure: V-reed

PARTEX DENIM


Pa

ge3

8

when cone rotates anticlockwise. There are three types of tension in warping i.e. catcher tension,

rod tension, and sacker tension. Magnetic tensioner is used for yarn tension. Then the yarn comes to

the winding zone or headstock. Combs straighten the yarns towards pressure drum, which supports

beam, and yarns in an alignment so that each and every yarn end can wound separately. Static

charges due to friction of yarns on metal surface cause static charges, which are removed through an

anti static device. Then the yarn is wounded on beam in this way for a required length if beam is

changed after one filling of beam then knotting of yarns is made. Similarly if cones are finished on

one frame side then trolley system of cone changing is used in this way chains rotates the whole

frame of empty side and new filled side of frame is forwarded again knotting is done between the

new cones yarn and already winded yarn. Extra yarn is then removed through cutting. Sensors sense

any type of yarn breakage and in case of yarn breakage knotting is done.

4.7.10 Count wise Drum Pressure:

Count Drum Pressure (daN) 6 500 7 500 8 500 9 400

10 400 12 400 14 400 16 400 20 350

4.8 Calculations: Some examples are given below to show the concept of warping plans.

Problem: 01

If Weight of Bag: 50 Kg

Total Number of Cone: 18

Count: 7 OE

Then find out the length of yarn in one cone.

PARTEX DENIM


Pa

ge3

9

Solution:

Length of yarn in one cone = Bag wt. × 2.2046 × .9144 × Count × 840

Total number of cone

= 50 × 2.2046 × .9144 × 7 × 840

18

= 32926 m

Answer: Length of 8 OE = 32926 m

Problem: 02

If Set length: 21000 m

Count: 7 9 12

Ratio: 4:4:4

Find out average count.

Solution:

Average Yarn Count = ( ) ( ) ( )

12 × 7 × 9 × 12

4 × 9 × 12 + 4 × 7 × 12 + 4 × 7 × 9

= 8.89

Answer: Average Count = 8.89

Problem: 03

If, Set length: 21000 m

Total ends: 4464

Ends/beam: 446

Total beam: 10

Count: 7 OE

Find out the weight of yarn required.

Solution:

Weight of yarn in one beam = Set Length × Total Ends × 1.0936

840 × 2.2046 × count

= 21000 × 446 × 1.0936

840 × 2.2046 × 7

PARTEX DENIM


Pa

ge4

0

= 790 Kg

Answer: Total Yarn Required = 790 x 10 = 7900 Kg

PARTEX DENIM


Pag

e 41

Chapter Five

Dyeing & Sizing

PARTEX DENIM


Pag

e 42

5.1 Definition: The process by which a textile material is to be changed physically or chemically, so that it looks mono

uniform colored is called dyeing. All commercial textile dyeing processes take place by the application of

a solution or a dispersion of the dyes to the textile material followed by some type of fixation process.

The dye solution or dispersion is almost always in an aqueous medium. A major objective of the fixation

step is normally to ensure that the coloured textile exhibits satisfactory fastness to subsequent

treatment in aqueous wash liquors. Dyeing is mainly depends on the type of fabric, structure of fabric

and the properties of dyes.

5.2 Objects of Dyeing: Ø The textile goods are dyed uniformly with single color.

Ø To increase the attractiveness of the textile goods.

Ø To make the fabric suitable for various usage.

Ø To make the textile goods suitable for decorative purposes.

5.3 Theory of Dyeing: The procedure by which dye stuff enters into the textile goods is called theory of dyeing. It is essential to

have certain degree of fastness properties when a dye particle is applied on textile goods. The whole

process of dyeing is completed by four steps as follows:

1. Dye molecules come to the fabric surface from the dye bath.

2. Fibre absorbs the dye molecule from the outer surface of the fibre to the internal surface of the

cellulose.

3. Migrates the dye molecules everywhere of the fibre molecules.

4. Anchoring or fixing the dye molecules to the fibre molecules by hydrogen or covalent bond.

5.4 Denim Dyeing: The classical jeans were produced out of indigo-dyed Denim fabric. The special character of this fabric –

only the warp thread is dyed makes it necessary to carry out dyeing in yarn form. The yarns applied for

Denim were exclusively produced on ring spinning machines in former times. The development of OE

yarns by applying smaller rotors with a spinning speed of up to 200 m/min has led to the application of

OE rotor yarns both for warp and weft. The yarns applied for weaving must be of high quality, a high

fiber for strength, regularity as well as a small part of short-stapled cotton fibres belongs to the basic

features of the denim yarn. For regular jeans qualities the warp yarns are spun in a fineness of 50 to 90

tex, for the weft yarn the fineness ranges are mainly 75 to 120 tex. If Denim is made out of Tencel or

Modal especially for jeans shirts the finenesses are up to 25 tex.

PARTEX DENIM


Pag

e 43

Indigo, sulphur and indanthrene are mainly used in the dyeing process. Two methods are applicable for

continuous dyeing with indanthrene dyes: rapid dyeing and vat dyeing. While processing the basic

colored denim, reactive dyes are used and fixed with hot caustic soda solution. The dyeing process is

mainly influenced by the dyestuff characteristics, dyeing temperature and necessary chemicals used in

the process. Indigo dye is the most popular choice as it has good depth of shade and suitable rubbing

and washing fastness.

When cotton yarn is dyed with indigo, it leaves a ring-dyeing effect, because of which the outer layer of

warp yarn is coated with indigo, and the core of the yarn remains undyed. This gives the denim garment

a unique ‘faded look’ and a rich blue shade after repeated use and wash. Originally, the warp yarns or

ends were put through the dye bath side by side to form a sheet of yarn, which passed continuously

through several dye baths, squeeze rollers or airing sequences. Specially two types of dyes are

commonly used in factory. Vat dye and sulphur dye. These two types of dyes are described below.

5.5 Dyes use for Denim: Ø Vat Dyes

Ø Sulphur Dyes

5.5.1 Vat Dyes: The name vat was derived from the large wooden vessel from which vat dyes were first applied. Vat

dyes provide textile materials with the best colour fastness of all the dyes in common use. The fibres

most readily coloured with vat dyes are the natural and man-made cellulosic fibres. Vat dyes are more

expensive and difficult to apply than other classes for cellulose such as directs, sulphurs, and reactive.

Indigo is a special case in the vat dye class. Indigo is attractive for its pleasing blue colour and for the

unique fading characteristics of garment dyed with it. Vat dyes are characterized by the presence of a

keto group. Vat dyes in keto form are water insoluble pigments.

Dyeing with vat dyes:

The application of vat dyes to cellulosic materials occurs in five stages.

Aqueous Dispersion:

The insoluble vat dye is dispersed in water.

PARTEX DENIM


Pag

e 44

Vatting:

This step involves the chemical reduction of the vat dye to produce the soluble, reduced or leuco form

of the dye. This is achieved by Sodium Hydrosulphite, Sodium Hydroxide and water. The sodium

hydrosulphite chemically reduces the vat dye in the alkaline conditions created by the presence of

sodium hydroxide.

Absorption of dye molecules by the fibre:

The vatted dye molecules are substantive to the cellulosic material when this is introduced into the dye

liquor. To achieve adequate exhaustion, an electrolyte is added to the dye liquor and the temperature

may be increased depending on the specific vat dye. The application of the dye molecule to the fibre

occurs at temperatures specific to a particular vat dye and occurs in a range from 200 C to 600 C. The

addition of the electrolyte alters the equilibrium of the dye liquor so as to increase the substantivity of

the dye molecules for the fibre. During this stage of dye application the textile material must be kept

immersed in the dye liquor to prevent premature oxidation of the leuco compound.

Re-oxidation of dye molecules within the fibre:

Once within the polymer system of the fibre the leuco form of the vat dye has to be oxidized and

converted to its original colour and the insoluble form of the dye. Oxidation of the leuco compound can

be achieved by atmospheric oxygen although this is somewhat slow. In practice, a mild oxidizing reagent

such as sodium perborate is used to convert the soluble leuco compound into the original insoluble vat

dye.

Figure: Water soluble leuco form of indigo

PARTEX DENIM


Pag

e 45

Soaping-off vat dyes:

During the previous stage some insoluble vat dye may be deposited on the surface of the textile

material. This has to be removed to prevent poor rub-fastness as well as a possible change of shade due

to the subsequent removal of this surface deposit. Soaping-off, which is the boiling of the dyed material

in a liquor containing some suitable detergent, removes this surface dye. The term soaping-off was

derived from the fact that before the development of detergents, soap was used to remove the surface

dye.

5.5.2 Sulphur Dyes: These dyes are so called because they contain sulphur atoms in their molecules. The fibres most readily

coloured with sulphur dyes are the natural and man-made cellulosic fibres.

Dyeing with sulphur dyes:

Sulphur dyes are widely used on cotton mainly because they are economical to use. They have good to

excellent wash fastness and good light fastness in dark shades. Light fastness of pale shades is poor.

Sulphur dyes are usually dull in shade since the molecular structures are complex. As a class, the sulphur

dyes are not resistant to chlorine containing bleaches.

Characteristics of Sulphur and LucoSulphur Dyes on Cotton:

Sulphur dyes have the dullest range of colours of all dye classes but are relatively inexpensive. They are

used to dye medium to deep, dull shades on cellulosic materials. There are several excellent blacks

giving dyeings with good wet fastness properties. In fact, when black, and deep brown, blue and dull

olive green shades are needed, with good washing and satisfactory light fastness at reasonable cost,

sulphur dyes are irreplaceable. There are few green sulphur dyes and no true reds. There are, however,

an abundance of blacks, blues, yellows and browns. On a world basis, sulphur dyes constitute one of the

major dye classes. Sulphur dyes are used in cotton dyeing for woven goods using jig dyeing machines

and also in continuous dyeing. They are commonly used for the continuous dyeing of corduroy. They are

now being used more widely in jet machines. Sulphur dyes are also used for dyeing denim olive, brown

and maroon, rather than the traditional Indigo blue, as well as to ‘bottom’ or ‘top’ Indigo dyed cotton

warps. To ‘bottom’ or ‘top’ means that a sulphur dye is applied either before or after the Indigo. The

fastness to wet processes and to crocking can be varied almost as required to satisfy the demand for the

faded look so popular for denim. This is achieved by allowing premature oxidation of the leuco dye

during dyeing, by using short dyeing times so that there is inadequate time for dye penetration into the

fibres, and by poor rinsing and soaping after dyeing. The dyeing can then be subsequently treated to

PARTEX DENIM


Pag

e 46

produce the faded worn look by removing the surface colour. Although cellulosic goods dyed with

sulphur dyes usually have good washing fastness, it can be further improved by resin finishing. The light

fastness varies from moderate to good in heavy shades. A major characteristic of sulphur dyes is the

poor fastness to chlorine, which distinguishes them from most quinone vat dyes. Dyeings with sulphur

dyes cannot be bleached with hypochlorite. In fact, these dyes are readily distinguished from other

cotton dyes by their dark, dull colours and the bleaching that occurs when a dyeing is spotted with

hypochlorite and allowed to dry. Cotton dyed with some sulphur blacks becomes tendered on storing

under warm humid conditions. This is a consequence of the formation of sulphuric acid from oxidation

of the sulphur dye in the fibres. It can be minimized by thorough washing after dyeing before the

oxidation of the leuco dye, by a final alkaline rinsing with soda ash solution, and by resin finishing. Such

tendering is avoided by dichromate oxidation of the leuco dye.

Dyeing with Sulphur Dyes:

Initially the goods are wet out in the bath. Since the dyeing liquor contains appreciable amounts of

sulphide, copper fittings must be avoided. If wetting or penetrating agents are used these should be of

the anionic type since non-ionic surfactants form stable, non-substantive complexes with the

leucothiols. An anionic product such as phosphated 2-ethylhexanol is suitable. The bath may then be set

at 40°C with some sodium polysulphide. Polysulphides in the leucodyebath prevent premature oxidation

of the dye and reduce the tendency to bronziness of deep dyeing of blues, navies and blacks. An

addition of a sequestrant such as EDTA avoids precipitation of the leucothiolate by calcium and

magnesium ions. The leuco dye is then added slowly and, since the leuco dyes only have low to

moderate substantivity for cellulose, some salt may be added initially, or in portions during dyeing, to

promote exhaustion. After dyeing the goods are rinsed, the leuco dye oxidised and the dyeing is soaped

as for a conventional vat dye.

Sulphur dyes usually have acceptable substantivity, particularly in the presence of salts, so that stripping

in a fresh reducing bath is not easy. Dyeing is often conducted at the boil but this decreases the degree

of exhaustion. Sulphur dyes require less salt than reactive dyes and usually have reasonable exhaustion.

Low sulphideleuco dyes require more salt and no polysulphide. They do not give good exhaustion in

heavy shades and the use of a low liquor ratio is recommended. For popular shades such as black, it has

long been common practice to use a standing bath. This is a dye bath that is re-used for subsequent

dyeings after addition of more reduced dye. Any free sulphur that tends to accumulate is dissolved by

addition of sodium sulphite to give thiosulphate. This prevents it sticking to the goods. The actual dyeing

temperature can vary. At higher temperatures around the boil, the bath exhaustion is less but

penetration of the leuco dye into the fibres is better than at lower temperatures.

PARTEX DENIM


Pag

e47

5.6 Denim Dyeing Process: There are three processes in the practice for continuous denim dyeing:

1. Rope Dyeing

2. Slasher or Sheet Dyeing

3. Loop Dyeing

5.6.1 Rope Dyeing: The indigo Rope dyeing technology for denim production is considered a superior dyeing technology, where better uniformity of dyeing is

achieved than other Indigo dyeing technologies like slasher dyeing.

Indigo rope dyeing was started in USA. Today rope dyeing accounts for a large percentage of warp yarn dyed for denim production. The system

offers highest production, due to continuous process, as there is no stoppage for set changes. In this dyeing method, maximum continuity of

shades and minimum danger of center to selvedge shade variation can be achieved. Flow diagram of rope dyeing is shown in figure. During

Figure: Rope Dyeing Range

PARTEX DENIM


Pag

e48

dyeing process, it forms a coating in the outer layers of the cotton yarn and fiber. This produces a ring of color around the cotton yarn, with the

core remains white core. This dyeing effect is known as ring dyeing.

Figure: Rope dyeing and subsequent sizing, Step 1: Ball Warper, Step 2: Rope Dyeing, Step 3: Long Chain Beamer, Step 4: Sizing

Indigo Rope Dyeing when dyeing according to the rope dyeing or cable dyeing method. 350 - 400 warp threads are bound on the ball warper to

very thick cables of 10000 - 15000 m length. On the continuous dyeing installation, 12 to 36 cables are led side by side, wetted, dyed and dried

after the dyeing process on cylinders and put into cans. Then the cables are dissolved to warps on the long chain beamer. The warps are added

to the sizing machine, sized and then led together to warp depending on the total numbers of threads. In practice, this method has proven to be

very good through obtaining an optimum indigo dyeing. However it is important that the cables have a constant tension in order to avoid warp

stripes. The disadvantage compared to other methods is that yarn breakages do occur more often.

PARTEX DENIM


Pag

e49

5.6.2 Slasher Dyeing:

In continuous slasher/sheet dyeing and sizing machine, direct warping beams are used, instead of ball warping logs in case of Indigo rope dyeing

system. The Slasher Dyeing machine is capable of handling Ne count form 9/s to 30/s (OE and Slub both). Typical schematic sheet dyeing range is

shown in Figure. At the back end of the slasher/sheet dyeing range, the direct warping beams are creeled. The yarns sheet from each beam is

pulled over and combined with the yarns from the other beams so that multiple sheets of yarns can be made. When dyeing according to the

sheet dyeing method, instead of cables the warp threads are fed to the machine parallel next to each other. These are much smaller compared

to the rope dyeing machines. Another advantage is that the cables don’t need to be open after dyeing.

Moreover, each yarn wets much faster and in this way reduces the dipping and wetting times during dyeing. All in all, each thread has a larger

surface compared to a dyeing cable and this requires somewhat more hydrosulphite to prevent a premature oxidation of the indigo.

Figure: Sheet Dyeing Range

PARTEX DENIM


Pag

e 50

5.6.3 Loop Dyeing:

In the loop dyeing process, the yarn is dyed in a single bath instead of several. The desired depth of color

is attained by passing the yarn through the vat several times. Subsequently, as a part of the same

process, the yarn is sized. The advantages and disadvantages of loop dyeing are the same as with sheet

dyeing.

5.7 Difference between Slasher and Rope Dyeing:

Comparison On Slasher Dyeing Rope Dyeing

Required Space Less More

Mercerizing Easy Difficult

Manpower Less More

Dye bath Less capacity More

Broken end repairing Not Possible In rope dyeing there is a possibility to repair broken end in LCB (Long Chain Beamer)

Flexibility Flexibility to produce denim in different colors and small quantities

Less flexible. Difficult to change colors.

Set change

Machines should start and stop at the time of set change. Hence shade matching is not easier until hundreds of meters of yarn run.

No need to start and stop the machine at the time of set change. Hence shade matching is easier.

Extra ends Extra ends Required. No extra ends.

Different colour mixing Not possible Possible to mix ends of different colours. One can get stripe design at re-beaming.

Count range Advantages for lighter yarn. Can use Ne 1-30 without major change.

Large numbers of yarns are difficult to open at re-beaming. Hence it is not suitable for fine yarn. Can use Ne1-16 without major change. In latest machines even higher yarn count can be dyed.

Rear view characteristics of fabric

Less thin / thick & knot points High thin / thick & knot points

Dye dipping time for effective dye result

< = 14s ( standard 10 – 14s regulated by speed)

< = 21s ( standard 15 – 21s regulated by speed)

Production capacity Approx. 9 to 11 million Metrs in case of normal capacity. Approx. 10 to 22 mill. Mt. in case of double capacity.

12 ropes = 9 to 11.5 mill. Mt., 24 ropes = 18 to 23 mill. Mt., 36 ropes = 27 to 34.5 mill. Mt.

Cost Cost of production is lesser compared to Rope Dyeing

Cost of production is more compared to sheet Dyeing

PARTEX DENIM


Pag

e 51

Relative merits and demerits:

Ø Generally rope dyeing denim range produces better quality of denim than slasher dyeing.

Ø Rope dyeing means for higher production and long runs. Ropes dyeing can more lots without

any stoppages at set change. In case of sheet dyeing, the machine remains stop at set change.

Ø In rope dyeing better dry and wet fastness properties in denim fabric can be achieved, than

sheet dyeing.

Ø In sheet dyeing good quality yarn is required, as mending of broken ends is very difficult in sheet

dyeing. This problem is less in rope dyeing.

Ø Sheet dyeing produces more waste than rope dyeing.

Ø Lot to lot, set to set shade consistency is better in rope dyeing,

Ø In sheet dyeing, there is a problem of center to selvedge shade variation. This can be caused due

to uneven nip pressure, non-uniform chemical and colour content in dye boxes. This problem

can also occur in rope dyeing as well. But proper rotation of the dried yarn cans at spreading

and winding and even distribution of warp yarns over the full width of the fabric minimize the

problem.

Ø The wetting and immersion time, oxidation time of dyed yarn are less in sheet dyeing due to

parallel warp threads.

5.8 Sizing:

5.8.1 Definition: The process of applying a protective adhesive coating upon the yarn surface is called sizing. This is the

most important operation to attain maximum weaving efficiency specially for blended and filament

yarns.

5.8.2 Objects of Sizing: Ø To improve the weave ability of warp yarn.

Ø To increase the tensile or breaking strength for cellulose yarn.

Ø To maintain good quality fabric.

Ø To reduce hairiness, weakness of textile materials.

Ø To remove electrolytic formation for synthetic or blended yarn.

Ø To increase elasticity.

PARTEX DENIM


Pag

e 52

5.8.3 Changes in Yarn due to Sizing: Ø Breaking strength: Increase

Ø Abrasion Resistance: Increase

Ø Stiffness: Increase

Ø Elasticity: Increase

Ø Frictional Resistance: Increase

Ø Yarn Diameter: Increase

Ø Extension: Decrease

Ø Electrostatic Charger: Decrease

Ø Hairiness: Decrease

5.8.4 Why Sizing is called Heart of Weaving? Ø Higher Strength

Ø Higher Elasticity

Ø Higher Smoothness

Ø Higher yarn diameter

Ø Higher weight of yarn

Ø Lower static electricity

Ø Lower weakness

Ø Lower absorbency

Ø Lower flexibility

Ø Lower hairiness

Ø Higher frictional resistance

5.8.5 Techniques of Sizing: There are several techniques to impart size materials into the yarn. These are:

Ø Hot melt sizing

Ø Foam sizing

Ø High pressure sizing

Ø Electrostatic sizing

Ø Emulsion sizing

Ø Combined sizing

Ø Slasher sizing

PARTEX DENIM


Pag

e 53

5.8.6 Types of sizing according to application: Ø Pure sizing: When sizing is done in yarn which produces unbleached fabric is called pure sizing.

So, ingredients are on the weight of yarn 7 to 10%.

Ø Light sizing: This is used for dyeing and printing. 11 to 15% sizing ingredients are used on the

weight of yarn.

Ø Medium sizing: For increase of strength and weight of the yarn 16 to 40% sizing ingredients are

used on the weight of yarn.

Ø Heavy sizing: It is used to increase the weight of yarn. Above 40% sizing ingredients are used on

the weight of yarn.

5.8.7 Size Ingredients and their function:

5.8.7.1 Starch or Adhesive:

The carbohydrate component extracted from certain plates is called starch. Example: Starch not maize,

corn, potato etc.

Function:

Ø To improve the strength

Ø To increase smoothness

Ø To increase elasticity

Ø To increase stiffness

Ø To impart adhesion

5.8.7.2 Softening Agents:

The agent which is used to give fabrics a soft handle and frequently smooth appearance is called

softening or lubricating agent. Example: Japan wax, tallow, lin seed oil, coconut oil, animal fats, mineral

oil, T.R.O., soap etc.

Function:

Ø To make the yarn soft and slippery

Ø To smoothen the yarn

Ø To reduce the stiffness

Ø To reduce flexibility and friction

PARTEX DENIM


Pag

e 54

5.8.7.3 Antiseptic or Anti mildew Agent:

The substances which prevent the mildew formation is called anti-mildew agent. Example: Carboxylic

acid, salicylic acid, Zinc chloride, phenol etc.

Function:

Ø To prevent mildew formation

Ø To prevent size material for a long time

Ø To help to store the size yarn

Ø To protect yarn from bacteria or fungi.

5.8.7.4 Hygroscopic Agents:

The agents which are used to moisture yarn and to prevent excessive drying of yarn is called hygroscopic

agent. Example: MgCl2, CaCl2, Glycerin etc.

Function:

Ø To moisture the yarn

Ø To prevent excessive prevent of yarn

5.8.7.5 Weighting Agents:

The agent which is used to increase weight of yarn and to impart the fullness and feel to the fabric is called weighting agents. Example: China clay, Sodium Sulphate, French chalk etc.

Functions:

Ø To increase the weight of yarn during finishing

Ø To impart fullness and to fell the fabric

Ø To prevent opening of the cloth.

5.8.7.6 Tinting Agents:

The agent which is used for the temporary coloration of textile materials is called tinting agents.

Example: Blue, Tinapol, Optical brightener etc.

Function:

Ø To increase the brightness and to remove the yellowish color of yarn

Ø To prevent dusting off

Ø To form a particular shade

PARTEX DENIM


Pag

e 55

5.8.7.7 Wetting Agents:

The agents which are used for uniform distribution of the sizing solution is called wetting agent.

Example: Sulphanol, soap, MgCl2 etc.

Function:

Ø To increase size exhaust

Ø To obtain a distribution of the sizing solution

5.8.7.8 Antifoaming Agents:

The substrates which prevent the foam formation is called antifoaming agent. Example: Pyridine,

Benzene etc.

Function:

Ø To prevent foam formation

Ø To give uniform size pickup

5.8.7.9 Neutralizing Agents:

This type of agent is used to neutralize the sizing solution.

PARTEX DENIM


Pag

e 56

5.9 Dyeing & Sizing in Partex Denim: In Partex Denim, dyeing of warp beam is carried out by Slasher dyeing process. World class Benninger

Slasher dyeing machines are using here. There are two slasher in this section. Normally it is said that in

Slasher dyeing shade variation is a normal practice but one who achieve the minimum variation is

market leader. Because it is very much economical than rope dyeing. So in less investment there is

margin of great profit. Slasher is normally operated at a speed of 30 m/min. There are two working

shifts in the department each of 12 hours a day. Input of dyeing department is beams from warping

department. Output of dyeing department is dyed warp sheet beams which are forwarded to weaving

department. It has well equipped dyeing lab. All controls of dying process is monitored from here by

computer.

Different portion and their model:

Machine Portion Model Name Creeling and linking Ben link Dyeing Ben indigo Sizing Ben size tech Dye kitchen Ben dye mix Total machine BenningerZeel

The salient features of the machine:

Ø Optimum dye fastness and uniform dyeing.

Ø High dye batch stability ensured by cross flow circulation and Continuous metering.

Ø Reproducible computerized process management.

Ø Multi color capability achieved by flexible process engineering.

Ø Environmentally compatible, due to low consumption of dyes and chemicals.

Ø User friendly design with low maintenance requirement.

Ø Optimum sizing and residual stretch.

Ø High output.

Ø Synchronized motors capable of running the machine at a constant speed.

Ø Easy drainage of liquor.

Ø Automatic dosing system.

Ø Re-storage of used dye liquor.

Ø Drying option after pre-washing, dyeing and sizing.

Ø Storage of 150 m long yarn sheet on accumulator.

Ø Automatic and manual controls of pressure of padders with electronic load cells.

Ø Quick creel change.

PARTEX DENIM


Pag

e 57

5.10 Machine Specification:

Brand name Benninger Zell Model Ben Indigo Year of construction 2005 Country of origin Germany Creel capacity 16 Speed of winding 1-50 m/min Warping width 1800 mm Maximum reed space 2600 mm Maximum beam diameter 1000 mm Number of dye bath 6 Total no. of boxes 13 No. of pre dryer 10 No. of post dryer 14 Air pressure required 6-8 bar Air consumption 15 m3/hr Steam pressure required 6 bar Steam consumption 5500-5700 kg/hr Water pressure required 2 bar Water consumption 20 m3/hr Electric power consumption 120 kW/hr - 190 kW/hr Production/day 40000 mtr/day

Machine Specification (Sizing part):

Brand name Ben size tech Machine Speed 30-40 m/min Squeeze Pressure 16.4 kN No. of Squeeze Roller 02 pair No. of Emersion Roller 02 No. Of Size Dryer 14 Preparation Tank Temperature 90OC Storage Tank Temperature 94OC Size Box Temperature 90OC Cooking Time 25-40 minute Refractor value & Ford cup value Measure the Solid % in size liquor

PARTEX DENIM


Pag

e 58

Machine process Sequence of Dyeing & Sizing

Three Post Wash Box

Sheet Dyeing process (Regular, Bottoming, Topping, Pure Black)

Three Pre Wash Box

Pre-beam creel zone

Sewing section

Benlink zone/ yarn welding area

Accumulator BL

Pre Wetting Box

Pre-drying cylinder

Accumulator TA

Size bath

Post drying cylinder

Accumulator BN

After Waxing Device

Yarn leasing area

Weavers beam winder

PARTEX DENIM


Pag

e 59

Some other assisting areas in the dyeing and sizing process are-

Ø Skying zone

Ø Dye kitchen

Ø Size kitchen

Ø Blower

Ø Reserves tank

Ø Size cooker

Ø Beam crane

Ø Yarn sheet spreader roller

Some other assisting areas in dyeing sections:

Ø Preparation Tank (K-905)

Ø Indigo stock solution tank (K-915)

Ø Black Stock solution Tank (K-920)

Ø Store Tank (K-925, K-930, K-935, K-940)

Reactor (K-910):

The dyestuff is prepared in stock solution tank, it may happen some times that the dyestuff may get

coagulate and the function of Reactor is to break the coagulated dyestuff.

There is a separate arrangement of- Hydrogen peroxide Tank, Acetic Acid Tank, D Black Tank, Reducing

agent Tank, Tenside, Caustic Soda, Normal water & Also Hot water (50o C) tank respectively.

5.10.1 Creel section: The beams are creeled in the creeling zone .There are 16 pre beams capacity. Pre-Beams are creeled

here. Pre-Beams are negatively moved by the tension of warp sheet from front side of m/c. Must have

to maintain same speed & tension on each pre Beam. Here is a control panel to control the speed of pre

Beam.

Figure: Creeling section

PARTEX DENIM


Pag

e 60

The beams can be controlled in groups or individually. The let-off can be individual let-off, single group

let-off or warp- round let-off. There are two creels present on the machine in order to replace the used

creel quickly with a creel on which beams are already installed.

The back beams are mounted in the back beam unit with insert able journals. The Unwinding tension is

imparted by pneumatically loaded and automatically regulated band brakes and break shoes. The upper

beam supports can be shifted pneumatically making it easier to mount the bottom beam.

Most important part of creel section is Benlink or yarn sewing section. Benlink is the process of joining

the previous warp sheet with next warp sheet.

5.10.2 Benlink: Benlink tape is used for this process. It is costly. Benlink tape heated for almost 46 min. Before Belting

Separating, rods are removed to pass through tape before entering warpers beam.

In case of ring Denim higher count is set at front side of creel section for example. If we use 7S, 9S, 12S

then first 4 pre beams contain yarn of 12S.

In case of slub; if we use 4 pre beam for slub then first 2 slub, then regulary again 2 slub at middle.

5.10.3 Accumulator: Here pairs of Roller moving ups-down to maintain proper tension on yarn. It also performs the storage

of yarn. There are 3 accumulators used, one is after creeling before dyeing next is after dyeing before

sizing and final one is after sizing before weavers beam. Dyeing & sizing is a continuous process.

Accumulator stored extra yarn by going up pair of R/r, during this time necessary work such

replacement of weavers beam is done, then again Accumulator come s its original position. Remember

that, for linear yarn tension of accumulator is low & for coarse Yarn, tension is high. Load cell Roller used

here for maintaining yarn tension.

PARTEX DENIM


Pag

e 61

5.10.4 Pre treatment: Pre-treatment process in sheet dyeing consists of treatment of the cotton yarn sheet with caustic and

wetting agent. Pre-wetting is carried out in order to get proper dyeing of the sheet. Pre-wetting is

carried out with a Wetting agent, at room temperature. Increasing temperature also increase the

In some cases, if well penetration of the dye is required, the yarns are treated with strong caustic soda

solution followed by hot wash and cold wash treatment prior to dyeing. The pH of the bath is 11.8-12.

Measuring roller Pressure roller

Figure: D-100, Pre wetting, Pre dyeing, mercerizing box

Squeezing roller

Window

Immersion roller

Feed roller

Safety device

Yarn separator roller

Yarn sheet

PARTEX DENIM


Pag

e 62

5.10.5 Pre-Washing (1-3 box): After pre treatment, pre-washing of the warp sheet is done. Pre washing is done in order to remove the

excess pre-treatment chemical from the warp sheet. If they remain inside the sheet than it will cause

the fibers to loose and also dyeing will not occur uniformly. Squeezing rollers are provided at the end of

each bath to remove the excess liquor from the sheet. These rollers also drive the warp sheet. Pressure

on these rollers is adjusted according to the tensile strength of the warp sheet with the help of load

cells.

Clod washing is done after hot washing in order to reduce the temperature of the warp sheet. Before

dying, washing is important for better penetration of dye molecules in the fibre.

Squeezing roller Squeezing roller

Immersion roller

Yarn separator roller

Yarn sheet

Figure: D-200, 220, 240 (Wash box)

PARTEX DENIM


Pag

e 63

5.10.6 Dyeing: As discussed above denim warp sheet is dyed with Indigo (Vat) dyes and sulfur dyes. There are some

options in dyeing of warp sheet.

Ø Indigo (Regular): In this case we use indigo in all tanks. According to shade.

Ø Bottoming: In this case another dye is applied before dyeing with indigo. First the warp sheet is

dyed with sulfur dye (black color) and then it is washed and then dyed with indigo.

Ø Topping: In this case the warp sheet is dyed with indigo in start and then it is washed and then it

is dyed with another dye (normally with sulfur).

Ø Pure Black: In this case the warp sheet is dyed with sulphur dye (black color) with high

concentration of color.

Washing is done after dyeing bath in order to remove unfixed dye. There are three wash box in this

machine. The wash boxes are similar as pre wash box.

Nitrogen Chamber Dye Chamber

Immersion roller

Squeeze roller

Dyed yarn sheet Undyed yarn sheet

Window

Figure: Dyeing box (D600 –D690)

PARTEX DENIM


Pag

e 64

Step 1 → Pre-wetting:

Bath Components Quantity

D - 100

Caustic soda (NaOH) (5-6) g/L Wetting Agent (Tenside) (10 -15) g/L Temperature (70-80) o C Squeezing Pressure (40-50) kN Normal Water As required

Total volume

Step 2 → Pre-washing:

Step 3 → Dyeing:

Step 4 → Post-washing:


D – 200 D – 220 D – 240

Normal water As required Squeezing Pressure 70-80 kN Temperature Room temp. Total volume/box

Bath Components Quantity D – 400 D – 420 D – 440 D – 460 D – 480 D – 490

Indigo ----(1.7-2.0) % shade pH 11.8 - 11.9 Temperature Room Squeezing Pressure (55-60) k N Water As Required Total volume/box 600 L


D – 600 D – 620 D – 640

Normal water As required Squeezing Pressure 70-80 kN Temperature Room temp. Total volume/box

Dyeing Recipe: Regular

PARTEX DENIM


Pag

e 65



D - 100

Black ----(1.5-2.5) % shade Reducing agent 10 g/L Wetting agent (Tenside) 5 g/L Caustic Soda 10 g/L Temperature (80-90)o C Squeezing Pressure (40-50) kN Water As required


Step 3 → Dyeing:


Bath Components Quantity D – 200 D – 220 D – 240

Normal water As required Squeezing Pressure 70-80 kN Temperature Room temp.

Bath Components Quantity D – 400 D – 420 D – 440 D – 460 D – 480 D – 490

Indigo ----(1.7-2.0) % shade pH 11.8 - 11.9 Temperature Room Squeezing Pressure (55-60) k N Water As Required



Dyeing Recipe: Bottoming

PARTEX DENIM


Pag

e 66



D - 100

Caustic soda (NaOH) (5-6) g/L Wetting Agent (Tenside) (10 -15) g/L Temperature (70-80) o C Squeezing Pressure (40-50) kN Normal Water As required


Step 3 → Dyeing:





D – 400 D – 420 D – 440 (Dyeing)

Indigo ----(1.3-1.4) % shade pH Squeezing Pressure Temperature Water

11.8-11.9 (60-65) k N Room As required

D – 460 (Normal wash)

Normal water Squeezing Pressure Temperature

As required 70-80 kN Room temp.

D – 480 D – 490 (Dyeing)

Black ----(1.7-1.8) % shade Reducing agent Caustic Soda Temperature Squeezing Pressure Water

Room temp. 25 g/L 22 g/L (80-90)o C (40-50) kN As required


D – 600 Normal water As required Squeezing Pressure 70-80 kN Temperature Room temp.

D – 620 Hydrogen Peroxide (H2O2)

D – 640 Acetic Acid

Dyeing Recipe: Topping

PARTEX DENIM


Pag

e 67



D - 100

Caustic Soda As required Wetting Agent As required Temperature (80-90) o C Squeezing Pressure (40-50) kN Water As required


Step 3 → Dyeing:





D – 400 D – 420 D – 440 D – 460

Black ----(4.0-6.0) % shade pH 12.8 - 13 Reducing agent 25 g/L Caustic Soda 20 g/L Temperature (80-90)o C Squeezing Pressure (40-45) k N Water As Required

D – 480 D – 490

Normal water Squeezing Pressure Temperature

As required 70-80 kN Room temp


D – 600 Normal water As required Squeezing Pressure 70-80 kN Temperature Room temp.

D – 620 Hydrogen Peroxide (H2O2)

D – 640 Acetic Acid For pH control

Dyeing Recipe: Pure Black

PARTEX DENIM


Pag

e 68

Dyeing Procedure:

At first necessary chemicals and water is given according to recipe in preparation tank. Then dyestuff is

prepared. K- 915 & K-920 are used for the preparation of Indigo& Black dyestuff respectively. For Indigo,

reducing agent is Sodium Hydrosulphite and for black, Reducing agent either Sodium Sulphide or

Glucose (only for Liquid Black). A good monitoring near preparation tank is necessary. Then both

preparation is taken to mixing tank from where goes to dye bath. Level is maintained between mixing

tank and dye bath. Sensor is attached with every bath which helps to maintain pH. Dye take up

happened form Dye bath due to continues yarn passing. Flow meter used to show reading of every

component like sulphur black, Reducing agent, Tensid, NaOH, Water.

There are some reserver tanks, known as buffer tank. Two buffer tank for dye, one for pre dyeing and

other for mercerizing. Then it is necessary to blank the mixing tank. At this moment, mixture goes to

buffer tank to storage.

To maintain recipe standard it needs continuous dozing. Dozing motor used for this purpose. It

maintained systematically, any shortage shown at flow meter, also shown at computer screen.

Necessary steps then taken.

N2 used at dye bath to prevent Indigo or black dyestuff fixation .There is a arrangement of sky roller

used for dye fixation & squeezing roller for removing excess dye. Before entering into the sizing box the

warp yams are dried out. This is known as pre-drying.

Cooking tank and dosing system:

A color kitchen is also known as cooking tanks. There are several cooking tanks are also provided with

the machine which is used for the preparation of liquor for pre-treatment, dyeing and sizing. They are

connected with the machine via dosing system.

The computer-controlled dosing system for dyestuff and chemicals is the heart of the machine. Indigo

vat, hydrosulphite and caustic soda are continuously added according to calculated quantity indications

and depending upon speed. Color Unlevelness owing to fluctuations in bath concentrations does no

longer occur. Owing to the high circulation rate of the dye liquor in two circuits, local bath concentration

differences are avoided. The metering control stores the required adjustment parameters and

guarantees a high level of process reliability and reproducibility.

The used dyes can also be preserved with the help of two storage tanks on the machine. Useless dye is

drained easily from the tanks with the pipes connected at their bottom.

PARTEX DENIM


Pag

e 69

5.10.7 Drying Zone: After wash box the yarns go through the dryer section. The wet yarns are dried by using cylinder drying.

Cylinder drying is done using steam heated hot rolls called the drying cylinders. The cylinders are coated

with Teflon to prevent sticking of the yarns on the cylinders. The drying zone contains 10 cylinders.

5.10.8 Accumulator: Accumulator is also known as compensators. After drying an accumulator is provided on the machine.

Whose function is to minimize chance of stoppage of machine because of the change of beam on the

head stock and insertion of rods in the leasing zone they accumulate the extra warp when the speed is

reduced from the headstock by moving assembly to upward direction. When the head stock is moved

with a greater speed the excess warp is removes from the accumulator.

5.10.9 Sizing: Although the quality and characteristics of the warp yarns coming out of the winding, warping and

dyeing processes are quite good, they are still not good enough for the weaving process for most of the

yarns. The weaving process requires the warp yarns to be strong, smooth and elastic or extensible to

certain degree. To achieve these properties on the warp yarns, a protective coating of polymeric film

forming agent (size) is applied to the warp yarns prior to weaving. This process is called slashing or

sizing.

One sizing tank is provided after the drying zone. The capacity of the size box is about 500 liters. Sizing

material is provided automatically by dosing system or it can be manually added.

Immersion roller Squeeze roller

Separator heated roller

Sized yarn sheet

Unsized yarn

Size liquor

Size bath

Safety guard

Feed roller

Figure: Size box

PARTEX DENIM


Pag

e 70

5.10.10 Size Cooking Process: At first different sizing agent according to recipe is taken manually in the mixing tank or preparation tank

and water is supplied by the pipe in the mixing tank. A fan circulated for mixing agent. Temp is

maintained in the mixing tank by steam. Then the mixed or prepared liquor is supplied to the storage

tank. From this storage tank liquor is supplied the size box by pump. The concentration of the size liquor

is checked by the refractometer because different concentration will have to use for different warp set.

The size liquor level in the size box has to maintain. The liquor in the size box is measured with a sensor

to regulate the specified level. There is a regulating Valve, it works on PLC (programmable logic circuit)

method. Generally size level is maintained by passing 180mm size liquor .when this level comes down

to 120-130 mm then regulating valve is open ,pass the size liquor & maintain the level. The temperature

of the size box is maintained by the steam. Simultaneously the application of the pneumatic squeeze

presser with air cushion cylinder to regulate the squeeze presser & achieve the uniform size pickup.

Relation between Count and Size Pick up%:

Count (Ne) Pick Up% 7 6-7% 9 8-11%

12 10-14% 16 12-18% 20 16-22%

Size Add On%:

Warp set (Count) size add on % 7,9 8 16 12

7,9,12 8 7,9,16 10

Ford Cup Value:

Time in Second Viscosity Level > 50 High viscosity

30-50 Medium viscosity < 30 Low viscosity

PARTEX DENIM


Pag

e 71

Controlling Point of Sizing:

Ø Viscosity of the size solution

Ø Sizing machine speed

Ø Size add-on levels

Ø Concentration of the size mixture

Ø Volume of the size box (both quantity and size level)

Ø Threading arrangements

Ø Volume of the size box (both quantity and size level)

Ø Condition of squeeze rollers

Ø Squeezing pressure

Ø Hardness of squeeze rollers

Ø Diameter of squeeze rollers

Ø Yarn count and size box warp density per unit space.

The important feature to be remembered during sizing:

Ø If the hairiness of the yarn is high then the concentration of the size would be high.

Ø If the twist is high in the yarn then the concentration of the size would be high.

Ø If the yarn (finer) count is high then the concentration of the size would be high & less Binder

Required.

Ø If the yarn (coarser) count is high then the concentration of the size would be low, more Binder

is required.

Ø If the temperature of the bath is high then the viscosity of the size would be less and vice versa.

Ø If the cooking time is more than the viscosity would be less.

Ø Increasing squeezing roller pressure decreasing size pick up %.

Refractometer:

A refractometer is a laboratory or field device for the measurement of an index of refraction. This meter

is used in sizing to measure the reflection of light in size liquor.

Figure: Refractometer

PARTEX DENIM


Pag

e 72

5.10.11 Drying Zone: After the size box the yarns go through the dryer section. The wet yarns are dried by using cylinder

drying. Cylinder drying is done using steam heated hot rolls called the drying cylinders. The cylinders are

coated with Teflon to prevent sticking of the yarns on the cylinders. The drying zone contains 14

cylinders.

5.10.12 Accumulator: After drying another accumulator is provided on the machine. Its function is same as previous.

5.10.13 Leasing Zone: Due to the nature of sizing, the yarns in the sheet may be stuck together at the exit of dryer section.

Therefore they are separated into individual ends using leasing rods. The individual sheets of yarns from

each section beam are separated.

5.10.14 Expansion Comb: Pins in the expansion comb separate the yarns within each sheet. With the expansion comb the warps

are spread according to the required width of the weaver’s beam.

5.10.15 Beaming: The yarns are wound on to weaver’s beam at the headstock. A pressing roller is pressing the warp yarn

for uniform tension winding. A guide roller guides the yarns to the weaver’s beam.

5.10.16 Transportation of Beams: After the winding of dyed warp beams the from the head stock the samples of the yarn are taken to

laboratory for testing and then it is transported to the weaving department.

PARTEX DENIM


Pag

e 73

5.11 Functions of chemicals used in Yarn dyeing:

Acetic acid:

Acetic acid is used to neutralize the pH.

Caustic Soda (NaOH):

Caustic soda is used with the reducing agent solution. The caustic soda react with the Leuco Vat acid at

the same time And the leuco vat acid form sodium salt of a leuco vat dye. This salt is water soluble.

NaOH is also responsible to rise the PH of the dye bath is about 11.8-11.9 (indigo) and 12.8-13.0 (Black).

In case of Bottoming, in pre dyeing bath Caustic Soda used, because black does not penetrate into the

fiber, caustic soda helps to penetrate.

Hydrogen Peroxide (H2O2):

Hydrogen peroxide is used as oxidizing agent and accelerates the fixation process. As a result dye

molecule is fixed with the material.

Reducing Agent:

Reducing agent is used in reduction reaction of water insoluble dye as like vat dye. Insoluble dye particle

is covered on the surface by another insoluble layer, the reduction is restricted to the available external

surface of the Vat dye particles. When the dye is treated with a solution of reducing agent (Na2S2O4)

surface of dye particles coming into contact with the solution and gets reduced & produced insoluble

Leuco Vat acid.

Wetting Agent:

Wetting agent helps to increase the uptake of the dye by the fiber. Here Tenside is used as wetting

agent. A continuous flow of Nitrogen is supplied to the dye bath in order to prevent oxidation.

PARTEX DENIM


Pag

e 74

5.12 Equipments used in dyeing lab:

Name Image Functions

Color Assessment Cabinet

Color fastness and shade match.

Metrohm meter

pH, Indigo and Hydro measurement.

Portable Spectrophotometer

Black color measurement.

ORP

Measure Oxidation Reduction

Potential

Metrohm pH meter

pH measurement

Digital Balance

Weight measurement

Desktop Computer

Machine control and dosing

command.

Micro Oven

Drying

PARTEX DENIM


Pag

e 75

5.13 Chemicals used for dyeing and sizing:

Dyes Auxiliaries Dyes

Commercial Name Commercial Name Acetic Acid Direfix SD Liq Caustic Soda Diresul Black RDT D-Liq Dicrylan V-HKN Diresul Brilliant Green RDT-H-Liq Den Wet SA (Wetting Agent) Diresul Brown RDT-Gs-Liq-150 Hydrogen Peroxide Diresul Red RDT-BG-Liq Ladiquest-1097 U Liq Diresul Yellow RDT-E-Liq Optifix EC Sulfotex Black SN-155 Reducing Agent DP GremDanim EFW Sequestarant (Secho-IND) Indigo Blue Sodium Sulphide Sulpher Black Powder Sodium Hydro Sulphite Wetto PBTS Wetto MR 48-B

Sizing Chemicals

Commercial Name Manufacturer Country Acrylic Size PCB PD PENTA CHEMICAL Pakistan Ben Tex K-2000 BENTEX Thailand Size Ben Tex B-120 BENTEX Thailand Size Ben Tex B-99 BENTEX Thailand Size Ben Tex B-60 BENTEX Thailand Native Tapioca Starch UGA Thailand Emsize E20 EMSLAND GROUP Germany Emsize E60 EMSLAND GROUP Germany

PARTEX DENIM


Pag

e 76

5.14 Calculation:

Problem: 01

Given,

Shade: 1.7%

Count: 7 OE

Total Ends: 4464

Set Length: 16400 m

Find required amount of dye.

Solution:

We know, Tex = 590.5

7= 84.36

Weight of 4464 ends = 84.36 4464

1000

×= 376.58 g/m

Weight of 16400 meter = 376.58 x 16400 = 6175912 gm

100 gm yarn contain 1.7 gm dye

1 gm yarn contain 1.7

100 gm dye

6175912 gm yarn contain 1.7 6175912

100

×gm dye

= 104990.504 gm dye

= 105 Kg dye

Answer: 105 Kg dye required to dye 16400 meter yarn of 4464 ends.

PARTEX DENIM


Pag

e 77

Chapter Six

Weaving

PARTEX DENIM


Pag

e 78

6.1 Definition: The process of producing a fabric by interlacing warp and weft threads is known as weaving.

The machine used for weaving is known as weaving machine or loom. Weaving is an art that has been

practiced for thousands of years. The earliest application of weaving dates back to the Egyptian

civilization. Over the years, both the process as well as the machine has undergone phenomenal

changes. As of today, there is a wide range of looms being used, right from the simplest handloom to

the most sophisticated loom.

6.2 Basic Weave Designs: Ø Plain weave

Ø Twill weave

§ Zigzag twill

§ Herringbone twill

§ Broken twill

Most of the other weaves are derived from these basic weaves. The immediate derivatives of these

structures are warp rib, filling rib, and basket weave.

6.2.1 Plain Weave: Plain weave is the simplest of all weaves. It has one-over one-under interlacing for both warp and filing

yarns, therefore the plain weave formula repeats on two warp and two filling yarns. Plain weave

requires only two harnesses. In Denim manufacturing this weave is called Chambray.

Figure: 1/1 plain weave (Chambray)

PARTEX DENIM


Pag

e 79

6.2.2 Twill Weave: Twill Weave is produced in a stepwise progression of the warp yarn interlacing pattern. The interlacing

pattern of each warp yarn starts on a different filling yarn and follows the same formula. These results in

the appearance of a diagonal line called twill line in the fabric, which is then characteristic of this design.

Depending on the direction of the twill line, the twill weaves are called right-hand or left-hand twills.

The sum of the digits in the formula determines the unit cell of the design, which also gives the

minimum number of harnesses, requires weaving the design; at least three harnesses are required for a

twill weave.

Common twill, Steep twill, Reclining twill and broken twill are the different variations of the twill weave.

6.3 Classification of Modern Weaving Machines: Modern Weaving machines are classified according to their filling insertion mechanism.

The classification is as follows:

Ø Rapier

Ø Projectile

Ø Air-Jet

Ø Water-Jet

Figure: 3/1 Right Hand Twill (RHT) Figure: 3/1 Left Hand Twill (LHT)

PARTEX DENIM


Pag

e 80

6.3.1 Air-Jet Weaving:

Air-jet weaving is a type of weaving in which the filling yarn is inserted into the warp shed with

compressed air. Air-jet system utilizes a multiple nozzle systems and a profiled reed.

Yarn is drawn from a filing supply package by the filing feeder and each pick is measured for the filling

insertion by means of a stopper. Upon release of the filling yarn by the stopper, the filling is fed into the

reed tunnel via tandem and main nozzles, which provide the initial acceleration. The relay nozzles

provide the high air velocity across the weave shed. Profiled reed provides guidance for the air and

separates the filling yarn from the warp yarn.

6.3.2 Rapier Weaving:

In Rapier weaving, a flexible or rigid solid element, called rapier, is used to insert the filling yarn across

the shed. The rapier head picks up the filling yarn and carries it through the shed. After reaching the

destination, the rapier head returns empty to pick up the next filling yarn, which completes the cycle. A

rapier performs a reciprocating motion.

Rapier weaving machines can be of two types:

Single Rapier Machines: A single, rigid rapier is used in these machines. The rigid rapier is a metal or

composite bar usually with a circular cross section. The rapier enters the shed from one side, picks up

the tip of the filling yarn on the other side and passes it across the loom width while retracting.

Therefore, a single rapier carries the yarn in one way only and half of the rapier movement is wasted.

Also there is no yarn transfer since there is only one rapier. The single rapier’s length is equal to the

width of the loom.

Double Rapier Machines: Two rapiers are used in these machines. One rapier, called the giver, takes the

filling yarn from the yarn accumulator on one side of the loom, brings it to the center of the machine

Figure: Relay Nozzles Figure: Rapier head

PARTEX DENIM


Pag

e 81

and transfers it to the second rapier which is called the taker. The taker retards and brings the filling

yarn to the other side. Similar to the single rapier machines, only half of the rapier movements is used

for filling insertion.

6.3.3 Projectile Weaving:

Projectile weaving machines use a projectile equipped with a gripper to insert the filling yarn across the

machine. The gripper projectile draws the filling yarn into the shed. The Projectile glides through the

shed in a rake- shaped guide. Braked in the receiving unit, the Projectile is then conveyed to its original

position by a transport device installed under the shed.

6.3.4 Water-Jet Weaving:

A water-jet weaving machine inserts the filling yarn by highly pressurized water. The relative velocity

between the filling yarn and the water jet provides the attractive force. If there is no velocity difference,

then there would be no tension on the yarn results in curling and snarling of the yarn. Water-jet weaving

machine can only be used for hydrophobic fibers.

6.4 Weaving in Partex Denim: In Partex Denim weaving is air Jet & Rapier. There are 132 airjet& 36 rapier machines. The department

is working under the good supervision of Mr. Paul who is weaving manager and very much dedicated to

his work. He is working with all his technical, management hardworking staff. Like some other

departments weaving department is running 24 hours a day and meeting the sales requirements.

Weaving department is playing a leading role in denim manufacturing at of denim at Partex Denim.

Figure: Projectile loom Figure: Water jet insertion

PARTEX DENIM


Pag

e 82

6.4.1 Specification of Airjet:

Brand name: : PICANOL

Model : OMP800-2P-190 Country of origin : BELGIUM Speed : 850 rpm Reed : Profile Reed Shedding : Cam shedding mechanism Air pressure required : 9.5 bar Total relay valve : 14 Number of heald shaft : 6 to 8 (Generally 3 to 4 used) Number of cutter : 2 Let off motion : Electrical Take up motion : Electrical

6.4.2 Specification of Rapier:

Brand name: : PICANOL

Model : GamMax-2P Country of origin : BELGIUM Speed : 650 rpm Reed : Flat Reed Shedding : Cam shedding mechanism Number of heald shaft : 6 to 19 (Generally 3 to 4 used) Number of cutter : 2 Let off motion : Electrical Take up motion : Electrical

PARTEX DENIM


Pag

e 83

6.5 Looming: Looming covers the process involved in warp preparation after sizing up to setting them to loom. The

process can be shown as follows:

Drawing-in → Warp Tying → Loom

During slashing, the exact number of warp yarns required in fabric is wound on to the loom (or

weaver's) beam. The warp ends are then passed through the drop wires of the warp stop motion, the

heddles of the harness frames and the dents at the reed. This can be achieved by drawing -in or tying -

in, the choice depending upon whether or not the new warp is different form the warp already on the

loom.

6.6 Drawing-In: The process of drawing every warp end through its drop wire, heddle eye and reed dent can be

performed manually or by means of automatic machines. In both case, a length of warp yarn, just

enough to reach to the other side of the frame, is unwound. Leasing (i.e. selecting warp) of the warp at

this stage simplifies the separation of the yarns. Then they are threaded through drop wires heddle eyes

and reed dents. The automatic drawing machine can handle the leasing-in and drawing -in process in

one single operation.

6.7 Tying-In: When fabric of a particular type is being mass-produced, the new warp beams will be identical with the

exhausted beams on the looms. Therefore, if every end on the new beam is tied to its corresponding

end on the old beam, the drawing-in process can be omitted. Tying-in may be done by means of a small

portable machine on the loom or as a separate operation away from the loom.

6.8 Basic Motion: In order to interlace wrap and weft threads to produce a fabric, the following motions are necessary on

any type of loom:

Ø Primary motions

Ø Secondary motions

Ø Tertiary motions

PARTEX DENIM


Pag

e84

6.8.1 Primary Motions: These are fundamental or essential motion. Without these motions, it is practically impossible to produce a fabric. It is for this reason that these

mechanisms are called “primary motion”.

Primary Motion

Shedding Picking Beating

Tappet Shedding

Dobby Shedding

Jacquard Shedding

Single Beating

Multiple Beating

Variable Beating

Over Picking

Under Picking

Modern Picking

Airjet Rapier Projectile Waterjet

PARTEX DENIM


Pag

e 85

6.8.1.1 Shedding Mechanism:

The shedding mechanism separates the warp threads into two layers or divisions to form a tunnel

known as ‘shed’. The shed provides room for passage of the shuttle. A shed may be formed by means of

tappets, dobby and jacquard.

Shedding Components:

There are two main shedding components:

Ø Heald frame

Ø Cam

The Heald or Heddle:

Alternate vertical movements according to the evolution of the warp yarn and the passage of the picks

drive the heddles. Healed frame or heddles consists of a wooden frame, which consist of healed wires.

To provide straight path for the passing of the warp. These are twisted and metallic wires, which slides

on flat bars within the frame.

Cam / Tappet:

The purpose of the cam is to control the motion of harness frames, the lift of reed and the weave

pattern. Possible weave patterns of fabric are 1/1, 2/1, 3/1 and 4/1. There are 4 cams in the air jet loom

and a single cam is double plated. The cam acquires special curved shape. Different cam setting can be

used for different weave pattern. It is the required condition that the machine revolution should match

with gear system gear ratio is adjusted according to the weave pattern.

Healed Shaft:

A healed shaft consists of a wooden or metal frame carrying healed wires. The width of a healed shaft is

slightly greater than that of the warp sheet and is usually 36 to 48 cm deep.

The functions of a healed shaft are:

§ To carry healed wires and maintain warp yarns in their correct positions

§ To form a shed line.

PARTEX DENIM


Pag

e 86

6.8.1.2 Picking Mechanism:

The picking mechanism passes weft thread from one selvedge of the fabric to the other through the

shed by means of a shuttle, a projectile, a rapier, a needle, an air-jet or a water-jet. The inserted weft

thread is known as “pick”.

Components of Picking Mechanism:

Cone Stand:

The purpose of this stand is to hold the cones. The main components of cone stand are:

Ø Cone holder

Ø Disc

Ø Tensioner

Cone Holder:

The shape of the cone holder is a little bit like an aero plane. It contains two propeller shape rubber

stopper so as to stop the forward and backward slippage of the cone during running condition and to

provide grip.

Plastic Disc:

The weft yarn from the cones passes through a plastic disc provided with the hole in the center the

purpose of this hole is to allow the weft yarn to pass through the disc setting of the disc is in such that at

a time of weft yarn from the first and fourth or the last weft yarn passes through the first and second

disc respectively. The distance between the discs can be adjusted with the help of the spring provided

with the nut. From the disc the weft yarn is delivered to the Tensioner.

Tensioner:

The use of tensioner is to give tension to the weft yarn otherwise the weft yarn coils within its self. This

tensioner consists of two small discs or plates. A spring is also provided at the side of one disc so that

the discs can adjust themselves according to the count of the weft yarn. If count is fine then low tension

is required whereas coarser count needed relatively higher tension. The alignment of the disc and the

cone is in such a way that a free path is provided to the weft yarn.

PARTEX DENIM


Pag

e87

Weft Yarn Path Diagram (Airjet):

Warp Yarn Path Diagram (Airjet):

FD1 FD2

Package

Package stand

Balloon Breaker

Pre winder Fixed Main

Nozzle

Movable Main Nozzle

Balloon Breaker

Filling Cutter Relay

Valve

Selvedge Cutter Relay

Nozzle

Yarn

PFT

Heald Frames Reed

Weavers Beam

Dropper

Back Rest

Stand

Fabric Yarn Sheet

Fabric Roll

Batcher

Emery Roller

PARTEX DENIM


Pag

e88

Weft Yarn Path Diagram (Rapier):

Warp Yarn Path Diagram (Rapier):

Heald Frames Reed

Weavers Beam

Dropper

Back Rest

Stand

Fabric Yarn Sheet

Fabric Roll

Batcher

Emery Roller

Package

Package stand

Balloon

Breaker

Pre winder Balloon Breaker

FT

Filing

Detector

Disk

Giver

Head

Taker Head

Cutter Cutter

Rapier belt

PARTEX DENIM


Pag

e 89

Cone Break Detector:

Cone break detector detects filling yarn breaks that occur between the cone and prewinder. The cone

break detector stops the weaving machine before the prewinder is empty. Cone break detector

between the cone and the prewinder prevents starts up marks.

The Filling Tensioner:

Filling tensioner are necessary to ensure a most uniform yarn tension between the cones and prewinder

drum, therefore ensuring an absolute uniform tension under filling yarn winding without any loop

formation.

Weft Accumulator or Prewinder:

The prewinder draw filling yarn from a cone, winding it on the winder drum which in turn, makes for

gentle pick insertion. The weft yarn is drawn off the package and wound on to measuring bands and

fingers by the rotating motion of thread guiding tube. The diameter of the measuring band can be

adjusted according to the width of the loom. Adjusting the measuring bands and the number of coils

sets the pick length. The electro magnetically controlled stopper pin releases the weft yarn at the

machine angle set.

Storage Control:

As it takes time to rise the motor rpm to the standard rpm at starting required weft yarn for next

insertion is wound in advance to secure smooth weft insertion. While the loom is running,

corresponding length weft yarn to one insertion is supplied to the prewinder, and storage is controlled

in the prewinder.

Measuring Control:

One pick length of weft yarn is measured by releasing or hooking solenoid FDP pin electrically. There are

two timings; one is for the first pick at starting and the other is preceding pick at normal operation.

These timings secure accurate measuring, storage, measuring and weft insertion are controlled by

output of signal command.

PARTEX DENIM


Pag

e 90

Balloon Breaker:

The balloon breaker reduces the balloon dimensions when drawing yarn from the prewinder. The closer

the prewinder to the balloon breaker, the smaller the yarn balloons. When weaving heavy filling yarns,

there is the potential to increase the rate of insertion when using a balloon breaker.

Main Nozzle:

Nozzle is a duct of smooth varying cross section in which air is used to accelerate weft yarn through the

shed across the width of fabric. On air jet weaving machines in each channel there are two main nozzles,

one is fixed and other is movable.

Relay Nozzles:

Relay nozzle mounted in sley are connected in groups to electromagnetic valves. The electromagnetic

relay nozzle valve starts the air jet. The length of time the valve is opened depends on the reed width

and relay valve spacing as well as on the yarn. The compressed air is distributed from the compressed air

tank via the valves to the nozzles.

Relay nozzles are arranged over the entire length of the reed, the relay nozzles assists the movable main

nozzle in blowing the pick through the reed guiding channel. These relay nozzles are divided up into

groups, in that each group of nozzle is served independently by a relay nozzle valve. These valves are

driven such that the rate of insertion is correct and that yarn flow is uniform.

Filling Cutter:

The function of cutter cuts the filling at the left hand and right hand side of an insertion. The cutter is

driven by the motor and is completely independent of the machine drive. The position, the movement

of cutting and the condition of the filling cutter are very important for the insertion. Cutter is mounted

on both ends of the fabric. On yarn supply side, yarn is securely cut every time reed is beaten. On driving

side preceding yarn is cut between the temple and the space roll. The motion of the cutter cam attached

to the main shaft is transmitted through cutter cam lever and cutter rod to cutter edge.

Filling Detectors:

The filling detectors or sometimes called feelers mounted at the reed holder on the loom and the end of

the driving side photo electrically monitors whether there is weft yarn arrive or not.

PARTEX DENIM


Pag

e 91

6.8.1.3 Beat Up Mechanism:

The beat-up mechanism beats or pushes the newly inserted length of weft thread (pick) into the already

woven fabric at a point known as “fell of the cloth”. These three mechanisms namely shedding, picking

and then beat-up are done in sequence.

Beating Components:

Sley:

The sley is a metal frame. In case of air jet contains profile reed, relay nozzles, filling detector, stretch

nozzle and side detector. At its forward motion the last pick is beaten up to the fell of the cloth, and at

its forward motion the weft is allowed to insert through relay nozzles through the open shed. The heavy

reciprocating sley with the help of a reed firmly beats up the last pick to the fell with the sufficient

velocity.

Reed:

The reed is an arrangement if vertical steel wires spaced a given distance apart a securely fastened at

the top and bottom by the bindings. The spaced between two wires is known as "dent". Reeds are made

with any desire number of dents per inch, according to the requirements of the cloth that is to be

woven. A reed contains a definite number of dents on a given length; this is termed as the count, the

pitch, or the number of reed. The reeds are named differently. Reeds are named from the number of

dents contained in one inch. The shape and thickness of the metal wires used in the reed is important.

Reed selection depends on several considerations including fabric appearance, fabric weight (ends per

unit width), beat up force, air space requirements and weave design.

PARTEX DENIM


Pag

e 92

Available Reeds in Partex Denim:

Reeds are very expansive machine parts and its correct use makes it long time running. In fine counts

reed damages very quickly. A good manager is that who runs his weaving shed with minimum number of

reeds rather than investing a large amount on reeds and storing them. In Partex Denim the shed of 168

looms is running on following reeds. With these reeds Partex Denim has made almost all of these orders.

Reed Count Dent per meter (DM)

Reed Space (mm)

590 1725 590 1742 652 1725 652 1742 869 1740 931 1739 1085 --- 1190 1738

6.8.2 Secondary Mechanisms: These mechanisms are next in importance to the primary mechanisms. If weaving is to be continuous,

these mechanisms are essential. So they are called the “secondary’ mechanisms”. They are:

Ø Take-up motion

Ø Let-off motion.

Secondary

Motion

Take Up Let Off

Positive

Negative

Positive

Negative

PARTEX DENIM


Pag

e 93

6.8.2.1 Take-up motion:

The take-up motion withdraws the cloth from the weaving area at a constant rate so as to give the

required pick-spacing (in picks/inch or picks/cm) and then winds it on to a cloth roller. The main part of

the mechanism is the take up rollers, which draws the cloth at the regular rate, and the number of picks

per inch decides this rate. The take up roller is covered with emery cloth or hard rubber depending upon

the type of cloth woven. The drive to the take up roller is by a train of gear wheels put into motion

directly from the main shaft.

6.8.2.2 Let-off motion:

The let-off motion delivers the warp to the weaving area at the required rate and at constant tension by

unwinding it from the weaver’s beam. The secondary motions are carried out simultaneously. The speed

of the servo motor is transmitted to warp beam gear via reduction gear, thus driving beam.

6.8.3 Tertiary Mechanisms: To get high productivity and good quality of fabric, additional mechanisms, called auxiliary mechanisms,

are added to a loom. The auxiliary mechanisms are useful but not absolutely essential. This is why they

are called the “auxiliary mechanisms”. These are listed below.

Ø Weft stop motion

Ø Temples

Ø Brake

Ø Warp stop motion

Tertiary Motion

Warp stop Weft stop

Selvedge motion Box motion

PARTEX DENIM


Pag

e 94

6.8.3.1 Weft stop motion:

The object of the weft stop motion is to stop the loom when a weft thread breaks or gets exhausted.

This motion helps to avoid cracks in a fabric.

6.8.3.2 Warp stop motion:

The object of the warp stop motion is to stop the loom immediately when a warp thread breaks during

the weaving process.

6.8.3.3 Brake:

The brake stops the loom immediately whenever required. The weaver uses it to stop the loom to repair

broken ends and picks.

6.9 Special Features of PICANOL:

6.9.1 Unique Sumo main motor: The oil-cooled Sumo main motor drives the weaving machine directly, without belt or clutch and brake.

The very short drive train is simple and compact, and the machine is up to full speed right from the very

First pick.

The speed of the motor is controlled electronically, without a frequency converter, thus reducing power

consumption and permitting greater flexibility. The shed crossing time is set entirely from the display.

This combination of the Sumo motor with electronic settings makes it easy to obtain the highest

possible industrial speeds taking into account the yarn quality, number of harnesses and weaving

pattern, and considerably reduces the set-up times.

6.9.2 Picanol PC Suite: Picanol PC Suite is a collection of PC software to monitor the design, settings and production data of the

weaving shed in a very easy way. LoomGate makes it possible to communicate between the PC and the

weaving machines over the network. Using LoomGate, machine settings are transferred from the PC to

the machines and vice versa, the weaving machine can be updated with new software, or the actual

settings and operating parameters of the weaving machines can be consulted. LoomGate also includes a

monitoring function to consult and process machine and shift production data on the PC.

PARTEX DENIM


Pag

e 95

6.9.3 Automatic full pick finding: The machine has an automatic full pick finder driven by the Sumo main motor. Pick finding is done using

a shiftable gear on the Sumo motor, so that no slow motion motor and clutch are required. In case of a

broken pick the machine stops and only the harness frames are brought in motion automatically so as to

free the broken pick, without the reed touching the beat-up line. This reduces the stop time in case of a

filling break and avoids starting marks.

6.9.4 Exchangeable shed formation: The PICANOL can be fitted with a positive cam motion, electronic positive dobby or electronically driven

jacquard. The basic machine structure for the cam, dobby and jacquard versions is identical, making it

possible to change the shed formation system at any time in the future. For example, it is possible

to change quickly from cam to dobby, and vice versa. It is even perfectly possible to convert to jacquard.

6.9.5 Electronic Let-Off and Take-Up: The electronically controlled let-off (ELO) and take-up (ETU) are fitted as standard. The ETU makes it

possible to weave fabrics with variable pick densities, with highly accurate settings.

6.9.6 Easy fitting and removal of warp beam and cloth roll: The warp beam is driven by an electronically controlled let-off system via a separate gearwheel that

remains on the machine. Fitting the warp beam and changing the cloth roll are done by means of quick

connections - no tools are required.

6.9.7 Perfect lubrication: Lubrication is by means of a central circulation system controlled by pressure and pressure difference

sensors. Constant filtering of the oil ensures perfect lubrication. The number of oil lines has been greatly

reduced, while the lines themselves are shorter and are made of remolded rubber.

6.9.8 Double pressure roller: The double pressure roller ensures a better grip of the sand roller onto the cloth. Because of the

division of the pressure of one pressure roller over two pressure rollers a zone contact is

established instead of a line contact (obtained with one pressure roller). This zone contact provides a

better control of take-up and allows weaving of heavily beat-up fabrics in an easier way.

PARTEX DENIM


Pag

e 96

6.9.9 Optimized sley drive: The sley is driven by a cam and cam follower system, for perfect beat-up and balanced lower inertia for

higher speeds.

6.9.10 Electronic Selvedge System and Electronic Rotary Leno: The unique Electronic Selvedge Systems (ELSY) are driven by separate stepper motors that are

controlled electronically. The selvedge patterns and crossing times can be programmed independently

of the shed crossing. This can be done even while the machine is running, so the weaver immediately

sees the result of the new settings. The crossing time of the Electronic Rotary Leno (ERL) can similarly be

programmed while the machine is running.

6.9.11 Quick Step filling presenter (Rapier): The Quick Step filling presenter operates with independent modules, each consisting of an electronically

controlled stepper motor with a presenter needle. The system handles up to eight colours. The operator

enters the weave pattern on the microprocessor keyboard or at the Jacquard control unit.

6.9.12 CANplus prewinders (Airjet): The CANplusprewinders have a sensor for the reserve windings and may have a built-in optical yarn

break detector. Thanks to the adjustable motion and force of the magnetic pin, the OMNIplus 800 is

able to weave yarns ranging from extremely light to coarse.

6.9.13 Programmable Filling Tensioner (Airjet): The Programmable Filling Tensioner (PFT) reduces the peak tension in the yarn at the end of

insertion when the magnetic pin on the prewinder closes. This makes it possible to weave weaker, more

delicate or elastic yarns at higher speeds. The PFT is automatically threaded along with the

prewinder when the latter is threaded pneumatically. The PFT is mounted on the balloon breaker

ensuring he ideal insertion line together with the fixed main nozzle.

6.9.14 Clamp on the movable main nozzle (Airjet): At the entrance to the main nozzle a pneumatically controlled mechanical clamp holds the yarn

during the non-insertion period, enabling the continuous airlow to be kept at a very low level. This

improves the fabric quality and reduces the number of stops with weaker yarns.

PARTEX DENIM


Pag

e 97

6.9.15 Argus filling detector (Airjet): The Argus filling detector ensures perfectly reliable detection of the yarn. The detector has a full view of

the entire cross-section of the insertion channel, so that detection is independent of the position of the

yarn in the channel. Argus is the new filling detector positioned next to the reed. It is mounted directly

on the reed holder. The Argus filling detector features 128 eyes covering a zone of 6.5 mm from the

back of the reed channel, compared to a detection zone of 2.5 mm for a standard model.

6.9.16 Fixed and movable main nozzles (Airjet): The entirely new air supply system and more efficient main nozzles permit higher performance. The

position of both the fixed and the movable main nozzles is simple to adjust. Moreover, the airjet

pressure and timing can be adjusted separately, giving reduced air consumption.

The Electronically-controlled Low Continuous Airflow (ELCA) system holds the filling yarn in the ideal

position during the non-insertion period. The digital setting for each channel prevents the yarn

unraveling.

6.9.17 New relay nozzles and valves (Airjet): The OMNIplus 800 relay nozzles are optimized for more efficient use of air. The shape of the nozzles

and the position of the holes give a higher Pitot value and enable maximum use to be made of the

available insertion time.

The new D-type relay nozzle has 16 holes instead of 19, which makes it more efficient for the same air

pressure. Air consumption can be reduced with up to 15%.

The new Diamond-Like Coating (DLC) on the relay nozzles ensures a significantly longer lifetime when

weaving abrasive yarns. The electro-magnetic valves on the relay nozzles have been redesigned and are

easy to reach, so that changing the width can be done quickly and easily. The airlines between valve and

relay nozzle have been made as short as possible, thus further reducing air consumption.

6.9.18 Adaptive Relay Valve Drive (Airjet): The new ARVD feature automatically optimizes the closing time of the relay nozzle valves related to the

behavior and the air friendliness of the weft. This program uses the winding information from the

prewinder in order to calculate the optimal closing moment of each relay nozzle valve on a pick by pick

basis. The relay nozzle valves will close earlier in case of a fast filling, consequently saving compressed

air.

PARTEX DENIM


Pag

e 98

6.9.19 Stretch nozzle (Airjet): The chimney stretch nozzle is fitted at the right-hand side of the reed and stretches the tip of the

pick at the end of insertion. Thanks to air pressure the yarn passes through a zigzag conduit in the

chimney and is stretched. It is frequently beneficial to include an extraction nozzle to the chimney

stretch nozzle. Combined with the programmable filling tensioner, the chimney stretch nozzle ensures

the best insertion for a filling yarn.

6.10 Different Parts Manufacturers Name:

Name Brand Heald Frame Heddle Frames

Dobby Stäubli Reed Burckle, Blue

Take Up Grob, Picanol Drop Wire Grob Air Blower Sohler, Electrojet

Winding m/c Brandt Knotting m/c Brand Fischer Poege

Electric Cable Supplier BBS Electronic

PARTEX DENIM


Pag

e 99

6.11 Selvedge: Selvedge is an important role for further processing of a fabric. Air-jet weaving machine can be equipped

with various types of selvedge formation devices. Several machinery manufacturers incorporate

different types of selvedge formation devices as per requirement of the end products.

Types of Selvedge:

Name Figure Application

Both end bounded Selvedge

(Handloom)

One end bounded (Rapier loom)

Fringed Selvedge (Rapier, Airjet)

Tucked-in Selvedge

(Projectile, Rapier, Airjet)

Fused Selvedge (for synthetic fabric)

Leno Selvedge (Rapier, Airjet)

Dummy Selvedge

(Rapier, Airjet)

Adhesive bonded Selvedge

Twisted Selvedge

Stitched Selvedge

PARTEX DENIM


Pag

e 10

0

6.12 Calculation:

Problem: 01

Given:

Ends per Inch (EPI): 66 Weave: 3/1 RHT Repeat: 4 ends Find required reed number?

Solution:

Repeat Per Inch = 66/4 = 16.5 Repeat Per Meter = 16.5 x 39.37 = 649.60 Available Reed = 652 DM

Answer: Reed number = 652 DM

Problem: 02

Given, Actual Production = 188773 pick Calculated Production = 192000 pick Find out efficiency?

Solution:

We know, Efficiency = Actual Production

× 100 %Calculated Production

= 188773

× 100 %192000

= 98.32 %

Answer: Efficiency = 98.32 %

PARTEX DENIM


Pag

e 10

1

Problem: 03

Given,

Fabric construction = 9 × 9

× 64"66 × 47

Weave = 3/1 R.P.M = 600 Efficiency = 80 % Find out production per hour in yards?

Solution:

We know production/hr= rpm × time x efficiency

PPI × 36

= 600 × 60 × .80

47 × 36

= 15.64 yds/hr Answer: Production Per hour per loom = 15.64 yds

Problem: 04

Given,

Fabric construction = 9 × 9

× 64"66 × 47

Weave = 3/1 R.P.M = 600 Efficiency = 90 % Find out weft yarn consumption in cone? Solution: Length of a pick = 72 “ Length of 600 pick = 600 x 72 = 43200 inch = 1097 meter

Weft yarn consumption in one minute = 1097 meter Weft yarn consumption in 60 minutes = 1097 x 60 = 65820 meter Weft yarn consumption in 8 hours = 65820 x 8 = 526560 meter

Length of 9 OE yarn in one cone = 42300 meter

Total cone required = 526560

× .9042300

= 11.20 = 12 cones

Answer: Total cone required = 12

PARTEX DENIM


Pag

e 10

2

Chapter Seven

Finishing

PARTEX DENIM


Pag

e 10

3

7.1 Definition: In general, before marketing, all the process which are applied on the fabric after weaving is called

finishing.

In short sense, finishing is the process by which the fibers, yarns and fabrics are made as presentable to

the customer and these processes are implemented after coloration.

The term finishing covers all those treatments that serve to impart to the textile the desired end-use

properties. These can include properties relating to visual effect, handle and special characteristics such

as waterproofing and non-flammability.

7.2 Objects of Finishing: Ø To increase the attractiveness of fabric.

Ø To increase the service ability.

Ø To increase the beauty and glitterness of fabric.

Ø To increase the fineness and to ensure smoothness.

Ø To ensure the softness of the fabric.

Ø To free from hairiness of the fabric.

7.3 Types of finishing:

7.3.1 Physical/Mechanical Finishing: The finishing process which is performed by machines but not using of chemicals is called

physical/mechanical finishing.

Example: Calendaring, embossing, raising, sanforizing etc.

7.3.2 Chemical Finishing: The finishing process which is performed by application of chemicals which reacts with fibres is termed

as chemical finishing.

Example: Starching, Mercerizing, resin finishing, Desizing, Water Repellent Treatment, Flame Retardant

Treatment, etc.

PARTEX DENIM


Pag

e 10

4

Denim Finishing:

Finishing of grey denim fabric normally carried out after weaving. It takes an important role in fabric

properties, appearance, softness and residual fabric shrinkage. The finishing of denim fabric is carried

out for several purposes. Finishing of denim fabric can be varied according to the specific requirement of

customer. The finishing process may vary from harsh hand (loom state), soft hand (desizing) and sulphur

over dyeing.

7.4 Finishing In Partex Denim:

Partex Denim finishing department is a well-established modern section with a suitable range of the

finishing processes required for denim. Department is working under the supervision of Mr. Mahfuz,

manager finishing.

Proper finishing process is necessary otherwise the fabric will be rejected by the buyer. In case of denim

mainly controlling of the shrinkage and the skew of the fabric is done. Besides, finishing process finishing

section of Partex Denim have to do a lot of others job like fabric storing, inspection, sample processing

etc. So a finishing section in a denim industry plays a vital role. Finishing section of Partex Denim Ltd is

responsible for the following:

Ø Finishing process

Ø Quality control

Ø Inspection

Ø Sample processing and preservation

Ø Finished fabric storing and delivery

The following types of finishes are applied to the denim fabric at Partex Denim.

Ø Singeing

Ø Softening

Ø Skew control

Ø Sanforizing

Ø Calendering

Ø Desizing

Ø Mercerizing

Ø Resin finishing

PARTEX DENIM


Pag

e 10

5

Flow Process Chart for Denim Finish Line

Fabric Unwinding

Brushing

J-Box

Singeing

Brushing

J-Box

Softening

Skewness

Dryer - 1, 2

Mini Stenter

Sanforizing

Calendaring

Folding

Protruding fibre removed by blower

Fabric store unit

Gas Pressure: 1-2 Bar Bust removed by blower

Bust removed by blower

Fabric store unit

Motor speed: 25-80 m/min

Softener Flacks used for soften the fabric

Strengthening the weft yarn

Steam pressure: 2 Bar

Control of fabric width

Fabric Shrinkage Control

Make the fabric surface uniform

Prepare for next step

PARTEX DENIM


Pag

e 10

6

Machine Specification:

Brand Cibitex

Origin : Italy Model : CBDENIM

Total machine : 02 Year of Manufacture : 2005

Roller width : 200 cm Working width : 180 cm

Steaming cylinder dia : 64 cm Shirking bench cylinder dia : 61.2 cm

Felt calendar cylinder dia : 200 cm Felt calender drying cylinder dia : 80 cm

Mechanical speed : Up to 80m/min Shrinkage value : Up to 18%

Average steam consumption at 6 bar : 1000 kg/hr Average soft water consumption at 2-3 bar : 5-6 m3/hr

Power consumption : 106 Kw

7.5 Process Sequence of Denim Finish Line:

7.5.1 Brushing: In the brushing stage, the grey fabric is brushed to remove the loose lint and loose fluff from the fabric

surface. It also raised the protruding fibers on the fabric surface which are removed in the next stage of

singeing process.

7.5.2 J-Box: Store the fabric for some while during the process. This unit is important when change of batcher.

Stored fabric supports the continuous operation.

7.5.3 Singeing: The fabric is then singed in both or only face side which burn off the protruding fibers from the fabric

surface. Normally denim fabric is singed twice in a single passage of a singeing machine. The denim

finished fabric must have soft and pleasant handle.

PARTEX DENIM


Pag

e 10

7

Reasons for Singeing:

Ø Textiles are first and foremost singed in order to improve their wear and end use properties.

Ø The burning-off of protruding fiber ends which are not firmly bound into the yarns results in

clean surface which allows the structure of fabric to be clearly seen.

Ø Fabrics which have not been singed soil more easily than singed fabrics.

Ø The risk of pilling, especially with synthetic fibers, is extremely low in case of singed fabric.

Ø A closely singed fabric is essential for printing fine intricate patterns.

Ø The risk of skitter dyeing with singed piece dyed articles in dark shades is considerably reduced

as randomly protruding fibres cause a diffuse reflection of light.

Ø Singeing process facilitates and speeds up desizing. This effect, however, is achieved only if the

fabric is impregnated with desizing liquor immediately after singeing.

Fabric before and after Singeing:

Types of Singeing:

Singeing can be classified into two types:

1. Direct singeing

2. Indirect singeing

1. Direct singeing is the most popular procedure. The fabric passes either glowing metal with contact

(mainly for pile fabric) or a direct gas flame. Important for both techniques: when the machine

stops, the fabric is moved from the metal and the flame stops, too.

2. The indirect singeing works with highly heated ceramic modules. Infrared beams are burning the

loose fibres. Speed controls the singeing effect.

Before Singeing After Singeing

PARTEX DENIM


Pag

e 10

8

Singeing Parameters:

Ø Fabric speed (m/min)

Ø Flame intensity (mbar)

Ø Fabric temperature (oC)

Ø Singeing positions

Ø Burner fabric distance (mm)

Singeing Techniques on Fabric:

Both side singeing Double singeing

PARTEX DENIM


Pag

e 10

9

7.5.4 Softening: After the singing range, the fabric is subjected to a chemical pad treatment. Softeners are often used in

the chemical treatment in order to impart soft feeling of the fabric.

7.5.5 Skewness Control: The skewness in denim fabric, particularly in twill weave creates a serious problem in subsequent

garment manufacturing and its washing. Leg twist is a major problem in denim manufacturing. Due to

this problem the leg is rotated in the opposite direction of the twill of the fabric after laundering. Leg

twist is assumed to be happen due to the directional yarn stresses. These are inherent in regular twill

weave fabrics and developed during weaving. During washing the yarn stresses is relaxed which change

the regular position of interlacement between warp and filling yarns. Due to this reason the legs are

twisted. Normally leg twist not shown on garment stage. It only observed after laundering of the

garment. Although leg twist appears after first laundering and it increases progressively with repeated

launderings.

Ideally warp and weft should be at right angle to each other in normal fabric. Skew in the fabric occurs

when the warps are displaced from their vertical position or when the weft is displaced from their

horizontal position.

The leg twist is created due to tensions in the fabrics. It is related to the twill direction. Normally a right-

hand twill fabric twists in the counter clockwise direction. Similarly a left-hand twill fabric twists in the

clockwise direction. These leg twist problem can be eliminated through compensating the tensions by

deliberately skewing the fabric in the counter clockwise direction for right-hand twills (RHT) and in the

clockwise direction for left-hand twill (LHT).

Hence the RHT denim fabric should be skewed by advancing the right selvage with respect to the left

selvage in the fabric of face up. This results in counterclockwise skew. Similarly a LHT fabric should be

skewed by advancing the left selvage when run face up. The amount of the skew to be applied depends

Figure: Fabric with skew Figure: Fabric without skew

PARTEX DENIM


Pag

e 11

0

upon many factors, such as the type of twill weave, the weight of the fabric, the yarn sizes, and the twist

of the yarns. The twill angle is also an important factor.

Normally the fabric straightness has only a single skew roller or a pair of rollers offset the same amount.

A single skew roller is not able to give a full 8% skew in a single passage in heavy weight denim fabric.

However, minimum two skew rollers, and preferably three or four skew rollers give better results.

In general, Z- twist cotton yarns generate right-handed skew. All S-twist yarns exhibit left hand skew. In

general open-end yarns result in less skew than the ring spun yarns.

When any woven fabrics are removed from looms, the warps and wefts start to contract each other in

order to undergo equilibrium condition. Hence the warp and weft yarn become closed to each other and

the free spaces between them reduced. It has observed that the type of deformation of fabric depends

upon many factors, among which the weave of the fabric (either plane or twill) is most important. The

forces acting on the yarns after removing the fabric from the weaving loom is shown in Figure.

Figure: Woven fabric skewness

Warp Contraction Force

Warp Contraction Force

Weft C

on

traction Fo

rce W

eft

Co

ntr

acti

on

Fo

rce

Forces acting on the yarns after releasing the fabric from the weaving loom

PARTEX DENIM


Pag

e 11

1

In case of plain weave fabric, the free spaces in warp and weft direction are equal. Hence the forces

acting on all sides of each float are equal, which makes the fabric more stable. However in case of twill

weave fabric, at the portion of a float; there is a gap or free space equal to the actual diameter of the

yarn. Due to this free space, there may be possible that the floating yarn push away the crossing yarn.

The two forces acting opposite to each other in the floats makes them like an in-plain lever (Fig. A). The

position of the free spaces on either side of the float determine the direction in which the float to be

skewed. For a right hand 2/2 twill fabric, the location of the free spaces, as shown in Fig. A will skewed

clockwise shown in Fig. B. For a left-hand 2/2 twill fabric, as shown in Fig. C, the floats will be skewed

anticlockwise.

Herringbone or any other types of zigzag twill, there is no risk of the fabric becoming skewed, as in such

weaves, floats (in-plane levers) act oppose to each other. The degree of skew movement depends upon

yarn characteristics, weaving tensions, and the fabric structures.

The movement of yarn in a plain fabric The movement of yarn in a twill fabric

The floating yarn to push away the crossing yarn at the interlacing point

Figure: A Figure: B Figure: C

PARTEX DENIM


Pag

e 11

2

7.5.6 Dryer: Wet fabric is dried in this section. Steam produced by boiler heating the cylinder drum. It increase the

inside temperature of the drum. The temperature can be adjusted by changing steam pressure. There

are 20 drums for drying.

7.5.7 Stenter: Stenter is used for control the width of fabric by fixing a definite width.

7.5.8 Sanforizing: Sanforizing is a mechanical finishing process of treating textile fabrics to prevent the normal dimensional

alternation of warp & weft. After sanforizing the residual shrinkage of woven fabric may be zero.

The sole objective of sanforizing is to control the length wise shrinkage of fabric. The maximum

percentage of shrinkage depends on fabric construction and quality but controlled according to the

customer specifications.

Shrinkage phenomenon:

During spinning, weaving, bleaching, dyeing and the various finishing processes, yarns and cloth are

under a continuous tension.

Yarns and/or fabrics are not fixed materials. They consist of separate, stretchable fibres which submit to

the tension. In other words, fabrics do stretch in length and width. The tension within the yarns, which is

caused by this stretching, can be eliminated when the friction within the fabric is reduced. This

reduction in friction occurs during laundering where both water and soap act as a lubricant. The

lubricant, along with the mechanical action of the washer, helps the fibres relax and contract to their

original length before the elongation takes place. This means that the fabric shrinks and recaptures its

original equilibrium.

Controlled Compressive Shrinkage Process:

The internationally well known and most important shrinking process today dates back more than 70

years. Though the correct expression for this process is Controlled Compressive Shrinkage, the average

person knows it as SANFORIZED. The process is a purely mechanical treatment without any addition of

chemicals.

PARTEX DENIM


Pag

e 11

3

The purpose of the process is to shrink fabrics in such a way that textiles made up of these fabrics do not

shrink during washing.

The amount of potential wash shrinkage must be determined prior to shrinking. A full width sample is

wash-tested according to the test method. After the lengthwise and widthwise shrinkage has been

determined, the compressive shrinkage machine can be adjusted accordingly.

Principle of Mechanical Shrinking:

The shrinking process takes place between the rubber belt and the heated shrinking drum. The pressure

roller presses the rubber belt against the shrinking drum and the belt is stretched. When the pressure of

the roller is relieved the belt shrinks again. The fabric inserted between the rubber belt and the drum

has to follow the shrinking of the belt and is itself shrunk. The fabric shrinkage can be varied by varying

the pressure of the roller on the rubber belt. The greater the roller pressure, the greater the shrinking.

The fabric is fed on the convex part of a drying cylinder and when the blanket retracts to the concave

section of the blanket, the cloth is physically forced to comply with the curvature and shrinks according

to the thickness of the blanket. The cylinder serves to hold the fabric on to the blanket and does not let

it slip back.

The excessive heat of the shrinking cylinder can cause damage to rubber belt. In order to prevent this,

perforated water pipes spray water on the belt as it leaves the fabric. This has two advantages;

Ø The rubber belt is cooled down and prevented from surface hardening.

Ø Very little water remains on the grainy surface of the rubber belt and absorbed by the fabric.

This results in good and easy shrinking process.

Figure: Shrinking process

PARTEX DENIM


Pag

e 11

4

7.5.9 Calendaring: After grey fabric is subjected to singeing, softening, skewness, sanforizing etc. it is finally dried to retain

its true shape and dimensions. But in this state the fabric becomes least lustrous. Because for those

operations the threads in fabric become weavy and crimped. But if a fabric is to appear highly lustrous

then its surface should be parallel to each other and all should lie in the length direction.

Objects of Calendaring:

Ø To cause a closing together of the threads of the fabric by flattening them and thus tending to

fill up the interstices between warp and weft.

Ø To produce a smooth, glossy and highly lustrous appearance on the surface of the cloth.

Ø To reduce fabric thickness.

Ø To reduce air permeability and water permeability of fabric by changing its porosity.

Essential elements of calendaring:

The following three elements should be controlled during calendaring.

Ø High pressure

Ø High temperature

Ø Suitable degree of dampness

Besides these the number, composition & arrangements of pressure bowls and speed of running cloth

are also should be controlled carefully.

Figure: Calendaring Process

PARTEX DENIM


Pag

e 11

5

7.6 Mercerization: Mercerization is a physio-chemical process where yarn (cotton) is treated with 15-25% caustic soda

solution at a temperature of 200-300C. It is necessary to hold the fabric under tension and wash

thoroughly.

Flow Process Chart for Mercerization

Fabric Unwinding

Bath-1

Bath-2

Bath-3

Stenter

Bath-4 to 7

Bath-8

Bath-9

Dryer - 1, 2

Fabric folding

Dosing of NaOH at room temperature

Dosing of NaOH at room temperature

Normal water wash at room temperature

Width control

Hot water wash at 90OC

Hot water wash at 90OC

Speed: 25-35 m/min

pH control

Normal water wash at room temperature

Moisture remove and drying

Prepare for next process

PARTEX DENIM


Pag

e 11

6

7.6.1 Physio-chemical changes during mercerization: When cotton fibre is brought into aqueous solution of sodium hydroxide of 18% concentration, the

cellulose begins to swell immediately and in a few seconds the fibre is elliptical in X-section. On further

swelling, the section rounds off and the major axis of the ellipse is at least 25-30% greater than the fibre

width of the corresponding collapsed fibre.

The cellulose of the wall sweels inwards until the lumen is practically eliminated.

When the fibre is transferred to water and well washed. Shrinkage begins and on drying at room

temperature a further and final shrinkage occurs. During the last three shrinkage proceeds uniformly

towards the centre and the lumen does not recover its original size.

7.6.2 Advantages of mercerization: Ø Increase tensile strength

Ø Improve hygroscopicity

Ø Improve dye affinity

Ø Improve smoothness

Ø Improve luster

Ø Improve dimensional stability and physical compactness

Ø 20-30% dye and chemical save while dyeing after mercerization.

7.6.3 Effect of mercerizing condition: The condition or considerable points for mercerization are:

Ø Concentration of caustic soda.

Ø Temperature

Ø Tension

Ø Time

Ø Wash thoroughly

Ø Wetting agent

The lusture of mercerized cotton depends on various factors:

Ø Cross-section of the fibre

Ø Staple length of the fibre

Ø Wall thickness of the fibre

Ø Concentration of caustic soda

Ø Temperature of solution

PARTEX DENIM


Pag

e 11

7

Ø Percent stretch

Ø Yarn construction

Ø Yarn twist

Ø Doubling of yarn

Ø Degree of singeing

Ø Application of tension

Ø Rate of dyring

7.7 Desizing: Desizing is the process of removing size materials from fabric. This is done simply passing the fabric

through some hot water bath for several times. Sometimes softener can be used for better removing of

size materials and also for better soft hand feeling.

Flow Process Chart for Desizing

Temporary fabric store

Normal water wash at 80-90 OC

Dryer, moisture remove

Prepare for next process

Fabric Unwinding

J-box

Bath-1-6

Dryer - 1, 2

J-box

Fabric folding

Temporary fabric store

PARTEX DENIM


Pag

e 11

8

7.8 Resin Finishing: Resin may be applied on the fabric surface to form a coating or it may be applied to the amorphous

region of the material to impart a crease resisting property. It is a permanent chemical finishing process.

Flow Process Chart for Resin

Fabric Unwinding

J-box

Fabric straighten roller

Roller Printing

Coating

Stenter/Heat setting

Rolling

PARTEX DENIM


Pag

e 11

9

Chapter Eight

Inspection

PARTEX DENIM


Pag

e 12

0

8.1 Inspection in Partex Denim: Quality is ultimate concern; every single yard of the denim goes through inspection department and

rated by a point count system to ensure that quality is up to standard before packing. Defective fabric

pieces are rejected and sold as seconds and relatively minor defective points are marked clearly using

stickers to alert cutters.

The inspection department is working under the supervision of Mr. Mahfuz, Manager, Finishing. Ten

inspection frames of Taiwan are used. Input is finished fabric & output is inspected fabric roll.

8.2 Inspection Process: Fabric batcher is set at the back side of machine equipped with rollers which provides fabric unwinding.

Inspection table is laminated white to enhance the defect identification. Four tube lights are provided to

optimize the lighting. Measuring counter is provided in front of the inspection table for controlling

length. It has forward, reverse, start and stop button controls. Inspection is carried out on white board

table. The cloth is pulled over the white board table by a variable speed motor and different cloth

defects are recorded for quality control purpose. They inspect the fabric according to 4 point system.

After inspection fabric is wound on roller.

8.3 Four (4) Point System: This is issued by the American Society for Testing and Materials with reference to the designation: ASTM

D5430-93.

Faults are scored with penalty points of 1, 2, 3 and 4 according to their size and significance.

Size Of Defect (Length in Inches) Penalty Points

3 inches or less 1 Over 3 inches but less than 6 inches 2 Over 6 inches but less than 9 inches 3 Over 9 inches 4

PARTEX DENIM


Pag

e 12

1

8.4 Machinery Description:

Inspection Table:

Name : Inspection m/c

Brand : STT Machinery Model : Amoeba M/C dimension : 2580 mm x 2920 mm x 2310mm(L×W×H) Speed : 0 - 80yds/min size of inspection board : 860mm (height) Motor power : 3 HP Roller width : 72 inch Fabric roll diameter : 450mm

Figure: Work Flow diagram

PARTEX DENIM


Pag

e 12

2

Wrapping Machine:

Shrinking machine:

Name : Wrapping m/c

Brand : STT Machinery Electric power : 9 KW Air consumption : 850L/min Speed : 5 - 6 packages/min Size : 970×2700×1300mm(L×W×H) Packing range : 38” - 70” (length), 100 – 400mm (dia)

Name : Shrinking m/c

Brand : STT Machinery Heat consumption : 45 KW Horse power : 1HP (main drive), 1/2HP ×2 (air blower) Speed : 5 – 18 M/min Size : 750 × 850 × 17500mm (L×W×H) Packing range : 38” - 70” (length), 100 - 400mm (dia)

PARTEX DENIM


Pag

e 12

3

Fabric Defects are divided into two types:

Ø Removable defects

Ø Non removable defects

The defects which can remove when inspection is called removable defects.

The defects which cannot remove when inspection is called non removable defects.

8.5 Major Fabric Faults: Starting mark:

Ø Causes: Main cause is loom stoppage.

Ø Remedy: This can not be avoided but can be controlled by starting mark setting.

Reed mark:

Ø Causes: If any fault occur at reed Faulty denting in the reed.

Ø Remedy: Right selection of the reed and right denting.

Snarl:

Ø Causes: Excess main nozzle pressure

Low filling tension

Ø Remedy: Main nozzle air pressure control

Correct setting of the PFT finger value

Double pick:

Ø Causes: Cutting problem of the cutter.

Faulty setting of the air pressure.

Ø Remedy: Cutter position is to be set correctly.

Air pressure should be reset.

Miss pick/ broken pick:

Ø Causes: Excess air pressure of main nozzle

Ø Remedy: Main nozzle air pressure should be reduced

PARTEX DENIM


Pag

e 12

4

Warp breakage:

Ø Causes: Bad sizing

Low strength of the yarn

Crossing of the warp yarn

Ø Remedy: Re knotting Proper sizing

Loose or Tight (sizing Fault):

Ø Causes: knotting is given, when yarn breaks, the yarn tension does not match with other yarn as

a result Loose or tight occurs.

Filling Stop:

Ø Causes: If weft is failed to reach FD1

If weft is too long & reach FD2

Ø Remedy: Correct setting of the weft length

Correct setting of main nozzle

Correct setting of relay nozzle

Proper setting of air pressure

Proper setting of pre-winder

Proper setting of creel position

Oil Mark or Crease, Hole:

Ø When fabric gets spots of oil lubrication from any part.

Contamination:

Ø It is a yarn fault, Plastic Others are mixed with yarn.

Patti:

Ø It is the dark color or thick weft lines in the fabric.

Crease Mark:

Ø Creases occur due to improper finishing.

PARTEX DENIM


Pag

e12

5

Department wise defects and codes no:

Yarn Dyeing Sizing Weaving Finishing

Defect Code no Defect Code no Defect Code no Defect Code no Defect Code no

Coarser warp 101 Shade variation 201 Loose 301 Broken pick 401 Crease 501 Coarser weft 102 Stain 202 Tight 302 Double Pick 402 Up singed 502 Finer warp 103 Stop mark 203 Beam stain 303 Miss Pick 403 Width variation 503 Finer weft 104 S.S.V 204 Size spot 304 Lashing 404 M/C Stop 504 Oily warp 105 Dyeing patta 205 Bad selvedge 305 Starting mark 405 Stain 505

Oily weft 106 Less width 306 Reed mark 406 Hole/Torn 506 Slub 107 Slack end 307 Knot 407 Sleeve mark 507 Contamination 108 B.F 308 Snarl 408 E.H mark 508

Smash 409 Weave 509

Stain 410 Bad selvedge 411 Floating end 412 Double end 413 Wrong drawing 414 Less width 415 Weave 416 Hole 417 Crease mark 418

PARTEX DENIM


Pag

e 12

6

8.6 Quality Assurance Procedure:

At first grey fabric is inspected thoroughly with the help of the inspection machine if any defect is

present there then the fault code number is written in inspection sheet.

When 100 yards fabric inspections is completed then stop the operation & fabric is cut by scissor. Next,

types & no. of fault is converted into point system as mentioned below. This point is expressed as

percentage by using the following formula:

Inspection Calculation Formula = Total Point × 36 × 100

Fabric length × Fabric width

Point Range Class Class Name Up to 20 Points / 100 m. Class A Elite Up to 20 – 30 Points / 100 m. Class B Zenith Up to 30 – 40 Points / 100 m. Class C Insta More than 40 Points / 100 m. Rejected Rejected

After calculation, the operator place the ‘Identification sticker’ on the fabric roll with mentioning details

of the fabric as Order no, Usable width, Fault grade, Roll length, Total point, set, style etc.

Finally, Fabric roll goes to packing section & then Stored or delivery.

PARTEX DENIM


Pag

e 12

7

Chapter Nine

Research & Development (R&D)

PARTEX DENIM


Pag

e 12

8

9.1 R & D Department in Partex Denim: Research & Product development department is an important department for any textile industry. This

plays a direct role on developing a product.

Partex Denim Ltd. has also a Research & Development (R&D) department with modern amenities which

correlates very well with the upcoming new product. Continuous research programmed is carried-on

here, which is completed by product development. The R&D department is independent and equipped

to promptly invent new designs for new fashion and develop buyer’s requirements timely. This

department keeps all documents from dyeing recipe to fabric construction and keeps master roll to keep

shade in same consistent even over a longer discontinuity. Partex always researches to develop new

fashion as per the world requirement as well as to maintain comfort & durability.

Most often this department creates new product on the basis of new design & structure by their own

creativity according to the current market demand and then give it to the buyer. If this design is

approved by the buyer then it is stored. They already developed over 5000 samples.

When an order comes from buyer in form of washed sample. The technical person determines the

shade percentage, amount and type of washing to that fabric to get the appearance like the sample. So

it is very important to wash the sample fabric to justify his assumption. For this purpose a small washing

unit is established in the factory.

Every order firstly comes into R&D department via marketing peoples by mail or swatch. The R&D

experts analyze these samples and match it with their developed samples. If they find similar samples

then this is sent to buyers for approve. If buyers approve it then the R&D section goes for production.

Figure: R&D department

PARTEX DENIM


Pag

e 12

9

9.2 Developed Samples:

The R&D department also performs different testing solutions. Most modern and efficient lab

instruments from Atlas, UK which is operated by trained technicians. The variable light box,

Spectrophotometer, Rubbing tester, Washing Fastness, Tensile strength tester etc. gives accurate results

and helps to keep quality good and more consistent.

Lab reports of a running lot are constantly maintained. After each process a sample for testing is sent by

the production staff usually after many meters of run.Lab reports contain information about various

tests performed according to buyer requirements and their results with remarks of responsible staff

about the fabric.

Samples according to Weave

3/1 (both RHT & LHT) 2/1 (both RHT & LHT) 2/2 RHT 3/2 RHT 4/1 RHT 1/1 chambrey Broken Twill Herringbone Twill Zigzag Twill Fancy Design

Samples according to Count

Regular – OE & Ring Slub Cross Slub Stretch Denim Polyester Denim

Samples according to Weight

4.5 Oz/Yd2 to 15.75 Oz/Yd2 Light weight: 4.5 Oz/Yd2

Medium weight: 7.5 Oz/Yd2

Heavy weight: 15.75 Oz/Yd2

Samples according to Color

Indigo Special Indigo Dark Indigo Blue Black Black Ash Reactive color denim

Samples according to Finish Coated Denim Printed Denim

PARTEX DENIM


Pag

e 13

0

The tests that can be performed are:

Ø Skew

Ø Weight (Oz/Yd2)

Ø Shrinkage warp%

Ø Shrinkage weft%

Ø Pilling ICI

Ø Tensile strength

Ø Wash fastness

Ø Rubbing Fastness

Equipments Used in R&D:

Ø Quickwash Plus

Ø Pilling Tester

Ø Rotawash

Ø GSM balance

Ø GSM cutter

Ø Shrinkage Measurement Scale

Ø Tensile Strength Tester

Ø Rubbing Tester

Ø Pilliscope

Ø Spectrophotometer

Ø Grey Scale

PARTEX DENIM


Pag

e13

1

9.3 Name of some Buyers:

Name Logo Name Logo Name Logo

Okaidi Marks &

Spencer

Tommy

Hilfiger

Tom Tailor Tosco

Next

VF Asia-lee

USA

Kappahl

Gap

USA

Ralph Lauren Charles

Vogele

Tema

Nautica H&M

Sweden

Wal-Mart

USA

Wrangler Zara

UK

Lindex

Uniqlo

Riders

Adams

Reef C&A

PARTEX DENIM


Pag

e 13

2

Chapter Ten

Denim Wash

PARTEX DENIM


Pag

e 13

3

10.1 Denim Washing: Partex Denim is not a washing plant although they have a small washing unit. It is just used for

product development and buyer swatch match. Though it is an important topic that’s why we

tried to give some information for understanding about Denim washing. Beside these washes,

Basic washes are carried out in Partex Denim which is described after the introduction part.

Basic Concept:

Denim has been used as clothing material for centuries due to its high durability. But today’s

fashion arena likes denim jeans due to its attractive shades, designs, attractive styles and

various types of wash appeal, rather than for its robustness. Denim jeans in the past were worn

in a raw, rigid and starch-finished form. But today’s fashion requires various types of washing

treatments, such as desizing, enzymatic washing with or without stones, decolorization,

neutralization, brightening and finishing.

Normally denim washing is carried out in sewn garments. The denim jeans are subjected with

different washing techniques, such as rinse wash, bleach, enzyme wash, acid wash, stonewash,

moon wash, sand wash, sun wash, over dyed/ tinted look, whiskering, damaged, used look. In

denim washing, enzymes played an important role to get clean, smooth, fuzz free fabric surface

with reduced tendency of pill formation and improved fabric handle. Traditionally, indigo denim

Figure: Washed denim

PARTEX DENIM


Pag

e 13

4

fabric is deep blue in shade. Denim finish may be of two types, such as raw denim and pre-

washed denim. In raw denim, the denim is not washed after weaving. Raw denim jeans shows

natural shade of indigo which is faded during wear and subsequent washes at home. However

in some cases it is believed that, raw denim is not practical as it creates some problems of rubs

off on other materials which come into contact with it. The unfixed dye on the surface of the

fabric may cause stains to other fabric.

In order to overcome this problems, denim jeans is washed after sewn. The main plus point of

pre-washing of denim jeans is that the colour is not transferred to other fabrics or surfaces

during wear.

10.2 Types of Denim Wash: Denim washing are of two different types.

1. Mechanical wash

2. Chemical wash

Chemical washes of denim fabric may be of different types.

Ø Denim Bleaching

Ø Enzyme washing

Ø Acid washing

Ø Rinse wash

Ø Cellulose wash

Ø Ozone fading

Ø Snow wash

Ø Salt water denim

Ø Flat finish

Ø Over dye

Ø Sun washing

Ø Super dark stone

PARTEX DENIM


Pag

e 13

5

Mechanical denim washes are stone washing and micro sanding. During stone washing, stones

are used in order to achieve typical wash down effect. There are three types of micro sanding,

such as:

Ø Sand blasting

Ø Machine sanding

Ø Hand sanding

Ø Whiskering

Ø Shot gun denim

Ø Water jet fading

Ø Super stone wash

Ø Ice wash

Ø Thermo denim

Ø Laser technology finish

Some important steps in the process of Denim Washing:

Ø Pre treatment (Desizing, Rinsing, Scouring etc.)

Ø Enzyme or Stone wash

Ø Clean up to adjust the desire effect

Ø Bleaching

Ø Tinting / Dyeing

Ø Softening & Much more

Pre treatment:

This is very first & basic step but most important step of washing. Here the fate of denim

garment is decided thatit’s going to appear good or bad. Good Pre treatments avoid streaking,

stiffness & color loss. This processremoves impurities, starch & stains during handling of fabric.

This step is also called desizing (Removal of Size applied during denim fabric making in weft

yarn). All the woven fabric contains size on them due to reasons to strengthen the yarn for

weaving. There are many types of sizes available in the market but they can be divided in two

major groups.

1. Water Soluble (CMC or PVA based sizes)

PARTEX DENIM


Pag

e 13

6

2. Dissolvable sizes in water (Starch based). Starch based sizes are most commonly used

due to cheap prices & readily availability.

Methods of Removing Sizes from Denim Jeans:

Ø Washing with High Alkaline agents (i.e. Soda ash)

Ø Washing with High Acidic agents (i.e. Acetic acid)

Ø Washing with Oxidative chemicals (i.e. Hydrogen Peroxide)

Ø Enzymatic desizing with Alfa amylase. This is eco friendly& convenient.

10.2.1 Desizing:

The sized denim fabric consists of cellulose fiber coated with a film of starch. Cellulose and

starch are chemically related. During weaving the warp yarns are subjected to considerable

stress and strain due to fast moving reed and other machine parts. In order to prevent the end

breakages, the warp yarns are sized. Although several other substances have been developed,

still sizing is still based upon starch. The starch makes the cloth less absorbent which impairs

the uptake of bleaches, dyes, and other chemicals. Hence complete removal of the size is

extremely essential.

There are various methods of desizing. Traditional desizing is carried out with acid, alkali or

oxidative desizing agents. However, these chemicals having some limitations and

disadvantages. The cellulose material may be damaged and loses strength with these chemical

treatments.

With the introduction of desizing with enzymes (amylases), the limitation and drawbacks of

traditional desizing process has been removed. The enzymatic desizing is considered to be the

best and safest. Conventional desizingdegrades the cellulose which is not occur in case of

enzymatic desizing. Enzymes are very specific in their action and act only on the starch without

reacting on cellulose.

The enzymatic desizing process is performed by using alpha amylase enzyme which hydrolyses

the cellulose. The enzyme desizing process offers high efficiency and specific action. Amylases

PARTEX DENIM


Pag

e 13

7

completely remove the size. These enzymes are harmless to the fabric and are environment

friendly.

Advantages of enzymatic desizing are:

Ø There is no adverse effect of enzyme on cellulose, on machinery and on other bath

auxiliaries. Hence loss of strength in desized fabric is minimum.

Ø In enzymatic desizing, multiple washing is not required to remove the residual chemicals

and hence there is saving of water in enzymatic desizing.

Ø Enzymatic desizing is carried out in moderate temperature, and the process time is also

reduced. This ultimately leads to increase in productivity and saving in energy.

Ø Neutralization is not required in enzymatic desizing.

Ø Enzymatic desizing offers softer feel and less hairiness on the fabric.

10.2.2 Bleaching:

Denim bleaching normally carried out with a strong oxidative bleaching agent such as sodium

hypochlorite or KMnO4. Bleaching may be carried out with or without the addition of stone. The

bleaching washing effect and de-coloration usually depends on strength of the bleach liquor,

liquor quantity, temperature and treatment time. The bleached fabric materials should be

properly antichlored or after washed with peroxide to reduced the subsequent yellowing or

tendering of the bleached denim fabric.

Limitations of bleaching:

There are some limitations of bleaching, such as:

Ø The same level of bleaching is very difficult to achieve in repeated runs.

Ø Bleaching treatment sometimes damage to cellulose resulting in strength losses and or

pinholes at the seam, pocket, etc.

Ø Bleaching liquor is harmful to human health. This may also causes corrosion to the

machine parts.

PARTEX DENIM


Pag

e 13

8

Ø Bleaching treatment needs antichlor treatment in order to eliminate the subsequent

yellowness to the fabric.

10.2.3 Stone wash:

Stone washing of denim fabric gives “Used” or “Vintage” look on the garments. This is due to

the varying degree of abrasion in the garment. The traditional stone washing of denim

garments normally carried out with pumice stones to achieve a soft hand and desirable look.

The pumice stones having oval and round shape with a rough surface, work as an abradant in

washing cycle. The variations in shape, composition, hardness and porosity gives different

washing effect in the denim fabric. During washing, these stones scrap off dye particles from

the surface of the yarn of the denim fabric which shows a faded, worn out and brilliance effect

in the denim fabric. Due to ring dyeing of denim fabric and heavy abrasion during stone

washing, the fading is more apparent but less uniform.

Figure: Bleach wash denim

PARTEX DENIM


Pag

e 13

9

In order to get the desired washed effect, the stone should be of proper hardness, shape, and

size. For heavy weight denim fabric large and hard stones are suitable and also last longer.

Similarly, smaller and softer stones are suitable for light weight denim fabrics.

The degree of colour fading during stone washing depends on several factors, such as, garment

to stone ratio, washing time, size of stones, material to liquor ratio and load of garments. The

washing time may varies from 40 - 120 min. Stones may be reused until they disintegrate

completely.

Pumice is a natural volcanic stone used for stone washing garments. It is crystallized with

substantive pores. Pumice is mostly used for stone washing due to its durability to chemicals

treatment, its strength and light weight.

Limitations of pumice stone usage:

Stone washing of denim fabric with pumice stones has some disadvantages and limitations,

such as:

Ø Stones may cause wear and tear of the fabric and may damage to washing machine due

to abrasion of the stone with fabric or machinery parts.

Figure: Stone wash denim & Pumice stone

PARTEX DENIM


Pag

e 14

0

Ø It may also create the problem of environmental disposition of waste of the grit

produced by the stones.

Ø Increase the labor cost to remove stone dusts from finished garments. The denim

garments is required to wash several times for complete removal of the stones.

Ø The stone washing process may cause back staining and re-deposition.

Ø The process is non-selective.

Ø Metal buttons and rivets in the denim garments as well as the drum of the washing

machine sometimes get abraded which substantially reduces the quality of the garment

and the life of the equipment.

10.2.4 Enzyme wash:

In order to minimize the adverse effect of stone-washing, the denim garments is washed with

enzymes. The enzyme breaks the surface cellulose fibers of the denim fabric and removes

during washing. During enzyme washing certain amount of indigo dye and cellulose fibers from

the surface of the fabric are removed.

Enzymes are proteins, found in all living organisms, plants, as well as animals and

microorganism. All organisms produce a wide range of enzymes. Enzyme washing is ecologically

friendly due to the natural origins of enzymes. Enzymes basically catalyse specific chemical

reactions and are known as ‘bio-catalysts’. Enzymes act on living cells and can be work at

atmospheric pressure and in mild temp and pH.

Figure: Enzyme wash denim

PARTEX DENIM


Pag

e 14

1

10.2.5 Sand Blasting:

Sand blasting is a mechanical process in which localized abrasion or colour change on the denim

garment is created. The process involves blasting an abrasive material in granular, powdered

form at a very high speed and pressure through a nozzle onto certain areas of the garment such

as knees and elbows. The garment treated surface shows distressed, abraded or used look. The

common blasting materials used are sand and metal granules.

During sand blasting process the garment are first subjected to stone wash to the desired

degree of washing. It is then sand blasted.

A solution of sodium hypochlorite or potassium permanganate often sprayed in desired area of

the garment in order to obtain the same look. The garment is then neutralized, rinsed softened

and dried. The sand blasting is a water free process therefore no drying required.

10.2.6 Acid wash:

Acid wash on denim jeans is becoming very popular due to its significant contrasts and

attractive appearance in color. Acid wash can be carried on Indigo &Sulphur base fabric

garments. Acid wash was a chemical wash process on denim which stripped the top layer of

color and makes a white surface while the color remained in the lower layers of the material,

giving it a faded look. Acid was first launched in 1980’s as a new innovative finish on denim

Figure: Sand wash denim

PARTEX DENIM


Pag

e 14

2

garments. This wash was being carried out by soaking stones in bleach and then followed by

neutralization.

Acid was of denim garment normally carried out by tumbling the garments with pumice stones

presoaked in a solution which contains sodium hypochlorite (5 to 10%) or potassium

permanganate (3 to 6%). This cause localized bleaching which produce non uniform sharp

blue/white contrast.

In this wash addition of water is not required. The color contrast can be increased by optical

brightening treatment. Acid washed denim fabric sometimes become yellowish after washing.

This is due to incomplete neutralization, washing or rinsing, so that manganese not removed

from the garment. However the manganese can be removed by washing with addition of

ethelene-diamine-tetra-acetic acid as chelating agent.

The process of acid washing jeans involves soaking of porous pumice stones and chlorine or

potassium permanganate (PP) bleach. Sodium-bisulfate is used for neutralization. It is

recommended to use two separate washing machines for Acid Washing & Neutralization etc.

Precautions:

During acid washing, the workers should wear mask & aprons. The operator should use

protective rubber gloves and safety glasses.

Figure: Acid wash denim

PARTEX DENIM


Pag

e 14

3

10.3 Denim Washing in Partex Denim:

When an order comes from buyer in form of washed sample the technical person determine

the shade percentage, amount and type of washing to that fabric to get the appearance like the

sample. So it is very important to wash the sample fabric to justify his assumption.

Partex denim only gives washed sample receipe so that buyer can get his desired design but

does not run mass production.

Three types of Sample washing are done in Partex Denims.

1. Enzyme wash

2. Bleach wash

3. Stone wash

A typical recipe for above three types of washing is given below:

Desizing

Chemicals Temperature Time Rinse Extracting Drying Anti-stain ET-2550

60-70 0C 20 minutes 2 Times 1 Time 60-800C Superzyme ultra plus

Enzyme wash


45 0C pH: 4.5-5

20-30 minutes

2 Times 1 Time 60-800C Eurozyme-1100L

Acetic Acid

Bleach Wash

Chemicals Temperature Time Rinse Extracting Drying

Bleaching powder

50-60 0C As required 3 Times 1 Time 60-800C

Peroxide Wash


50-550C As required 2 Times 1 Time 60-800C Caustic soda

Hydrogen peroxide

PARTEX DENIM


Pag

e 14

4

Neutralization

Chemicals Temperature Time Rinse Extracting Drying

Sodium Thiosulphate

Room 5 minutes 2 Times 1 Time 60-800C

Softening

Chemicals Temperature Time Rinse Extracting Drying Euro N5 soft

50 0C 5 minutes 2 Times 1 Time 60-800C Euro Silk -2660

Ø Enzyme wash has to be done for dark shade.

Ø Bleach wash has to be done for light shade

The above function is maintained very efficiently by R & D department.

10.4 Chemical Used for Washing:

Name Origin Antistain ET-2550 G-Tex Kem. Bangladesh

Euro Silk-2660 G-Tex Kem. Bangladesh

Superzyme Ultra Plus G-Tex Kem. Bangladesh

Eurozyme-1100L G-Tex Kem. Bangladesh

Euro NS Soft G-Tex Kem. Bangladesh

Eurozyme N-315 G-Tex Kem. Bangladesh

Sodium Thiosulphite (Hypo) China

Sodium Meta-bi-Sulphite BASF Germany/Turky

Caustic Soda Thailand/China

Bleaching Powder KCI, India

Acetic Acid Bangladesh

Hydrozen Peroxide Bangladesh

Soda Ash Light Nirma, India/China

Pumic Stone Indonesia

Imacole C-2G Clarient, Thailand

PARTEX DENIM


Pag

e 14

5

10.5 Machine used in washing unit:

Industrial Washing Machine

Features:

Ø Single door design for general washing, sweater and sample washing machine.

Ø Automatic washing timer and pre-set front and backward rotation.

Ø Option to install 4 steps gear box or frequency controller for speed control for different

requirement of garments.

Industrial Washing Machine:

Features:

Ø 2 doors, 2 chambers design

Ø Special for sand wash purpose

Ø Automatic washing timer and preset front and back rotation

Ø Option to install 4 steps gear box or frequency controller for speed control for different

requirement of garments

Ø Option with water level ruler

Figure: Industrial washing machine

Figure: Industrial washing machine

PARTEX DENIM


Pag

e 14

6

Industrial Water Extractor:

Features:

Ø Special Design for Industrial Laundry

Ø Stainless steel inner basket, durable and strongly built

Ø Equipped with shake absorbing spring

Ø With hand clutch for fast-stop

Ø Installed with insulated motor and automatic clutch for fast start and longevity

Industrial Drying Tumbler:

Features:

Ø Preset forward and backward rotation of inner basket.

Ø Stainless steel inner basket, clean and durable Equipped with thermostat.

Ø Solenoid steam value set for steam save and temperature control.

Figure: Industrial water extractor

Figure: Industrial drying tumbler

PARTEX DENIM


Pag

e 14

7

10.6 Most Common Denim Washes:

Washing Type & Features Application

Fraying:

It is a type of finish in which some selected area of denim jeans have been sanded to create a “worn” effect. In others words fraying is the destruction of denim fibers in a selected areas, such as waistbands, pockets or hem of the jeans.

Sand wash:

Denim sand wash is carried out with pumice stones, enzymes and sand in combination. This gives a aged look in denim jeans.

Rinse wash:

Rinse wash denim is washed at about 500C in a hot bath. Sometimes softener is used to soften the fabric.

PARTEX DENIM


Pag

e 14

8

Most Common Denim Washes:


Over-dyed / Tinted Denim:

Over-dyeing / tinting of denim is an additional dyeing treatment which is normally carried out on jeans after sewn. This add another tone of color to the jeans. Normally denim garments is over-dyed with yellowish dye for appearing dirty look. Tinted / over-dyed denim garments shows a used / vintage & muddy look to the garments. During tinting, a little amount of tint or color is added to the garment in order to change the hue/cast/tone of indigo shade.

Torn Jeans:

Some jeans are teared at some places in order to get natural tearing look. The fabrics have actual rips, holes, tears and/or lacerations.

Vintage Denim:

It is a type of denim washing in which the denim garments is subjected to heavy stonewashing or a cellulose enzyme wash, with or without bleach for showing an old and worn out look.

PARTEX DENIM


Pag

e 14

9



Destroyed/damaged/used/whiskers:

Whiskering, also known as 'Cat's Whiskers', are the crease lines around the crotch. Whiskering can be done on the sides of knee and crease marks on the back of the knee. During natural wear, in the portion of a crease, Pigment is removed. Denim garments can be made of old, worn and /or used look by several different ways, such as with the help of laser, sandblasting, machine sanding, hand sanding or abrading by some kind of power tool. With the help of a grinder, whiskering can be produced around the hip to crotch area of the pant. Damaged look of a denim pant can be made by cutting the edges at different areas before washing, such as at bottom, pockets, fly and knee area.

Flat Finish:

Flat finish of denim fabric involves mercerization plus calendaring processes to achieve the flat surface. It imparts an even wash down effect and clean surface. The mercerization process swells up the cotton fibers which is pressed in calendaring to achieved a flat surface.

Ozone Fading:

In this technique of denim washing, the garment is bleached with ozone dissolved in water in a washing machine. However this technique can also be carried out in a closed chamber by using ozone gas. The advantages of these methods are: There is minimum loss of strength It is a simple method and environmentally friendly. The ozonized water after laundering can easily be deozonized by UV radiation.

PARTEX DENIM


Pag

e 15

0



Super Dark Stone Wash:

This type of denim wash offers an extra dark indigo color which is obtained from a double-dyeing technique.

Super Stone wash:

It is type of wash treatment of denim garments in which the denim garments is subjected to prolonged stonewash treatment for more than six hours. Soda ash and soap are used for hard wash. Steam is used up to 60-80 0C for one hour to finish the washing process. It is followed by acetic acid wash treatment, then the garments are neutralized and rinsed.

Dirty wash:

In this washing process, after stone-washing treatment, the denim garments are dyed with special chemicals. This shows a dirty looks to the garments.

PARTEX DENIM


Pag

e 15

1



Laser marking/Spray painting:

Laser marking/Spray painting is a computer controlled technique through which different patterns or designs, such pictures, images, lines, text etc. can be developed on denim garments. It is also called spray painting in denims. In this technique chemicals or pigments is sprayed on the fabric in order to get different pattern on the garments. This is followed by curing of the garment. The advantages of the systems are:

• It is a water free process. Hence it is an It is an

ecological and economical process. There is zero effluent discharge.

• As this process in computer controlled, the

chances of human error is negligible.

• This system having excellent reproducibility and higher productivity.

• The machine requires less maintenance and cleaning.

• Consuming less time. • This technique having no adverse effect on

fabric strength.

Ice Wash:

Ice washing is a type of denim washing in which almost half the dye is removed during washing.

Water-jet fading: In this method of water jet fading, one or both surfaces of the denim garment are exposed through hydro jet nozzles. This hydro jet treatment gives a patterning effect to the garments and /or improves the surface finish, texture and durability of denim garment. This process is not involved with any chemical, hence it is environmental friendly and more economical. The required colour fading is achieved without affecting the fabric strength or durability, or warp shrinkage.

PARTEX DENIM


Pag

e 15

2



Quick Wash Denim:

In normal indigo dyed denim is associated with various problems during washing. The denim fabric manufacturers are in search to develop a new dyeing method in which the wash cycle can be minimizes. In this regard, Quick wash denim has been introduced in which the fabric is dyed with modified technique of dyeing, so that during wash cycle, indigo dye can be removed easily during a shorter washing cycle. Quick wash treatment procedure consumes less water and chemicals and required less time for washing, retaining fabric strength. By controlling the ionic form of indigo and cellulose in the dye-bath, the uniformity of indigo dyeing can be achieved. The alkalis used and pH conditions of indigo dye-bath produce stable color yield. Advantages of quick wash denim:

• Quick wash denim requires less indigo dye. The washing treatment also requires less enzymes and oxidizing agent. Hence it is an economical and environment friendly process.

• The development of streaks in garments after washing has been avoided by using a modified alkali-ph controlled system giving uniformity of shade.

• The washing time is 20-30% less than conventional denim.

Snow Wash:

This type of washing treatment for denim is a variation of acid wash. It gives bright white highlights.

Sun Washing:

Sub washing of denim fabric imparts a sun faded appearance to denim garments. It is carried out by bleaching and stoning of the denim garments.

Soft feel denim:

Soft feel denim can be made with the addition of softener at the garment stage.

PARTEX DENIM


Pag

e 15

3

Chapter Eleven

Utilities

PARTEX DENIM


Pag

e 15

4

11.1 Definition: The definition of utilities can be expressed in many ways.

• A company that generates, transmits and/or distributes electricity, water and/or gas from

facilities that it owns and/or operates.

• An economic term referring to the total satisfaction received from consuming a good or service.

Production and profit are closely related. In order to get a quality final product, it needed fresh raw

materials as well as effective manpower and machinery in good working condition. Utility plays a vital

role to maximize the production as well as the profit.

A utility system used in industrial facilities. This area includes boilers, chillers, cooling towers, air

compressors, and their associated fluid distribution systems.

Utility department of Partex Denim Ltd. is related to the following things:

Ø Electricity : Gas Generator, Rural electrification Board (REB)

Ø Water : Deep Tubewell

Ø Gas : TITAS

Ø Steam : Boiler

Ø Compressed air : Air compressor

Ø Chiller

Ø Humidification plant

Ø Workshop

Ø Effluent Treatment Plant (ETP)

Ø Water Treatment Plant (WTP)

11.1.1 Water Supply: Water is supplied by deep tubewell. There are two tank main & reserve tank for water storage. The level

of water is monitoring continuously and reading is taken in every hour. A daily report is prepared for

that and this water is supplied to many sections like dying, boiler, generator, compressor etc

• Total water consumption: 700m3/day.

PARTEX DENIM


Pag

e 15

5

11.1.2 Boiler: A steam generator or boiler is usually a closed vessel made of steel for supplying steam. Boiler function

is to therefore the heat produced by the combustion of fuel (here gas is used) to water and ultimately to

generate steam. The steam produced in the boiler section supplied to different section of mill.

Supplied sections for steam:

Ø Sizing

Ø Finishing

Ø Dyeing unit

Ø Washing unit

Ø Chiller

Specification of Boiler:

Brand : MechMar Country of Origin : Malaysia + England Year of manufacture : 2005 Model : AS 2400/150 (24000 PPH) Fuel used : Natural Gas Power consumed : 25 kWh Maximum steam output : 10.8 ton/hour Water content : 15.45 m3 Fire tube : 130 Maximum heat capacity : 6.5 MW Maximum working pressure : 10 bar Gas pressure : 1.3 bar Total tube : 130 Air: Fuel 4:1 Sparking input power : 240 V (AC) Sparking output power : 1000 V (DC)

Key Features:

Ø Designed and manufactured to the latest international standards.

Ø Full wetback design thus minimizing radiation heat loss and refractory maintenance.

Ø Large furnace volume assures high combustion efficiency and for a wide variety of fuels to be

burnt efficiently.

Ø Compact in construction yet designed for easy access, important for internal inspection,

cleaning and maintenance.

Figure: Boiler

PARTEX DENIM


Pag

e 15

6

Ø Full automated operation provided for control for burner system, steam pressure and for

failsafe operation.

Working Principle of Boiler:

In boiler gas is used as fuel. The gas pressure of main line is high. A regulator is used to lower the

pressure then the gas feed to boiler's burning unit. The heat produced in the burning unit raise the

temperature of the water of closed vessel. And convert the water into steam. The steam is then going to

header. Steam for different machine like dyeing, sizing, finishing etc supplied from here. Some steam is

going to economizer and the steam from economizer go to the feed tank which increase the

temperature of water of feed tank up to 60OC – 65OC. So when this water will feed to the closed vessel,

it will be easy to make it steam. Water from feed tank comes to water vessel through gate valve, check

valve and feed pump. There are two feed pump, both of two should not run simultaneously.

11.1.3 Generator: An electrical generator is a machine, which converts mechanical energy into electrical energy. The

energy conversion is based on the principle of the production of dynamically induced e.m.f. When a

conductor cuts magnetic flux, dynamically induced e.m.f. is produced in it according to flow if the

conductor circuit is closed.

Features:

Ø 12 cylinders turbocharged and intercooled

Ø Fully integrated engine diagnostic and control system including:

• Spark timing control

• Turbocharger control

• Speed governing

• Individual cylinder knock detection

• Air/Fuel ratio control

Ø Fuel tolerance

Ø High altitude capability

Ø Low Btu option

Ø Rich burn combustion

PARTEX DENIM


Pag

e 15

7


Brand : Waukesha Total machine : 04 Country of Origin : USA Year of manufacture : 2005 Fuel : Natural Gas No. of inline cylinder : 6 Firing Order : 1R-6L-5R-2L-3R-4L-6R-1L-2R-5L-4R-3L Capacity : 900 kWh Volt : 50 H.Z & 400 Volts Speed : 1000 rpm

Working Principle of Generator:

In generator to produce induced e.m.f. it is required to cut the magnetic flux by conductor. For this

reason the conductor needs to move. For this movement a mechanical energy is required. This

mechanical energy supplied by burning gas. Gas is supplied with a specific pressure. A serious amount of

heat is produced due to the combustion of gas. This heat is cool down by a cooling tower. Water is

continuously circulated and removes the heat.

11.1.4 Air Compressor:

Compressed air along with gas, electricity and water is essential to most modern industrial and

commercial operations. It runs tools and machinery, provides power for material handling

system and ensures clean breathable air in contaminated environment. In Partex Denims rotary

screw compressor is used.

Figure: Generator

PARTEX DENIM


Pag

e 15

8


Brand : Kaeser Country of origin : USA Year of manufacture : 2005 Total machine : 08 Compressor Output : 20.5 m3/min/mc Dryer Output : 52.5 m3/min/mc Output Pressure : 9-9.5 bar Power Consumption : 132 kWh/mc

Rotary Screw Compressor:

The main element of the rotary screw compressor is made up of two close clearance helical-lobe rotors

that turn in synchronous mesh. As the rotors revolve, the air is forced into a decreasing inter-lobe cavity

until it reaches the discharge port.

Features:

Ø With one-to-one drive, the air end is directly connected to the motor via a maintenance-free coupling that eliminates transmission losses.

Ø Direct drive screw compressors deliver outstanding performance and increase energy savings. Ø It uses oversized air ends specifically selected to produce the required output in flow and

pressure. Ø Compared to compressors using small, high-speed, gear-driven air ends, the one-to-one drive

provides significant savings. Ø No-loss power transmission. Ø Lower power consumption. Ø Reduced maintenance and related downtime costs.

Cooling section

Control Unit

Reduced Voltage Starting

Inlet Filter

Airends Motor

Direct Drive System

Figure: Compressor

PARTEX DENIM


Pag

e 15

9

Dryer:

The atmospheric air drawn into a compressor is a mixture of gases that always contains water vapors.

However, the amount of water vapor that air can carry depends on the temperature. As air temperature

rises – which occurs during compression – the air's ability to hold moisture increases also. When the air

is cooled its capacity to hold moisture reduces which causes the water vapor to condense. Removing the

moisture from the compressed air not only prevents costly breakdowns and production downtime, but

also keeps maintenance and repair costs to a minimum. Refrigeration drying is usually the most efficient

solution for the majority of compressed air applications.

Figure: Dryer

PARTEX DENIM


Pag

e 16

0

Features:

Ø Low pressure drop, non-fouling heat exchanger.

Ø Low pressure drop filtered separator with microprocessor controlled filter monitor removes

liquids and particulates to 3 microns.

Ø "No-loss" electronic Eco-Drain for reliable condensate removal.

Ø On/off load digital scroll refrigeration compressor (Dual Control models only).

Ø Hot gas bypass control (Demand Manager models only).

Ø State-of-the-art control system with timed auto-start and stop.

Ø Optional cold coalescing oil removal filter eliminates oil aerosols to 0.008 ppm.

11.1.5 Chiller:

A chiller can be generally classified as a refrigeration system that cools water. Similar to an air

conditioner, a chiller uses either a vapor compression or absorption cycle to cool. Once cooled, chilled

water has a verity of application from space cooling to process use.

There are two types of chiller:

• Vaporisation Chiller

• Absorption Chiller

In Partex Denim Ltd. the absorption type of chiller is used.

Specification of absorption chiller:

Brand : LS Model : LSH-W036S Origin : Korea Year of manufacture : 2005 Cooling capacity : 300 usRT Chilled water flow rate : 181.4 m3/h Chilled water temp. : 7-12OC Cooling water flow rate : 334.7 m3/h Cooling water temp. : 32-37OC Heating source : Steam Steam consumption : 1357 Kg/h Steam pressure : 8 Kg/cm2G

PARTEX DENIM


Pag

e 16

1

Chiller Tower Specification:

Brand : Spacco Model : SPC 600 RT Year of manufacture : 2005 Capacity : 2060 m3/h Water in : 37OC Water out : 32OC Fan motor power : 20 HP Air Capacity : 132400 m3/min

Working Principle of Chillers:

Absorption chillers are used to generate cold water (44°F) that is circulated to air handlers in the

distribution system for air conditioning.

Absorption chillers use heat instead of mechanical energy to provide cooling. A thermal compressor

consists of an absorber, a generator, a pump, and a throttling device, and replaces the mechanical vapor

compressor.

The basic cooling cycle is the same for the absorption and electric chillers. Both systems use a low-

temperature liquid refrigerant that absorbs heat from the water to be cooled and converts to a vapor

phase (in the evaporator section). The refrigerant vapors are then compressed to a higher pressure (by a

compressor or a generator), converted back into a liquid by rejecting heat to the external surroundings

(in the condenser section), and then expanded to a low- pressure mixture of liquid and vapor (in the

expander section) that goes back to the evaporator section and the cycle is repeated.

The basic absorption cycle employs two fluids, the absorbate or refrigerant, and the absorbent. The

most commonly fluids are water as the refrigerant and lithium bromide as the absorbent. These fluids

are separated and recombined in the absorption cycle. In the absorption cycle the low-pressure

refrigerant vapor is absorbed into the absorbent releasing a large amount of heat. The liquid

refrigerant/absorbent solution is pumped to a high-operating pressure generator using significantly less

electricity than that for compressing the refrigerant for an electric chiller. Heat is added at the high-

pressure generator from a gas burner, steam, hot water or hot gases. The added heat causes the

refrigerant to desorb from the absorbent and vaporize. The vapors flow to a condenser, where heat is

rejected and condense to a high-pressure liquid. The liquid is then throttled though an expansion valve

to the lower pressure in the evaporator where it evaporates by absorbing heat and provides useful

cooling. The remaining liquid absorbent, in the generator passes through a valve, where its pressure is

reduced, and then is recombined with the low-pressure refrigerant vapors returning from the

evaporator so the cycle can be repeated.

PARTEX DENIM


Pag

e 16

2

11.1.6 Humidification Plant: Humidifier is a system to provide proper humidity and temperature in a working space. To maintain the

proper humidity and temperature in a weaving mill is very important. Different electrical circuit board of

weaving machine cannot work for a long period without proper temperature and humidity. Proper

humidity helps to remove the producing static electricity due to friction of different machine parts.

Working Principle:

There are three dampers in the humidification plant. By two damper airs from outside into the plant

and. by another one re circulated air again supplied to the plant. There is a passage to a cooled water

sprayed area. Here the cooled water (6-7OC) is sprayed to the air. The cooled water is supplied from the

chiller. Then this cooled air pass in the weaving section by duct line. The air from the conditioned space

(weaving section) again sucked by the underground duct. This air is full of dust, lint, fibre etc. Then a

filter a part of this air again re circulated in the plant filters this air and rest of the air is leave to the

outside.

Area Total Machine Consumption per machine

(kWh) Total Consumptions

(kWh) Warping machine 2 25 50 Dyeing machine 2 100 200 Loom 168 ---- 600 Finishing (Cibitex) 2 150 300 Finishing (Mercerizing) 1 150 150 Finishing (Coating) 1 150 150 Finishing (Desizing) 1 150 150 Inspection 10 --- 50 Lighting --- --- 80 Compressor 8 132 1050 Chiller 2 75 150 Humidifier 2 150 300 Boiler 2 25 50 E.T.P --- --- 25 W.T.P --- --- 25 Power produced by Generator

4 900 3600

Total Power consumption

3330

PARTEX DENIM


Pag

e 16

3

Effluent Treatment Plant

(ETP)

PARTEX DENIM


Pag

e 16

4

Introduction:

In this industrialized age, environmental pollution is a matter of great concern. Surface water

pollution is one of the elements of environmental pollution. Chemical processing industries

especially textile processing industries are claimed to produce huge effluent to discharge in our

rivers. A complex mixture of hazardous chemicals both organic and inorganic is discharged into

the water bodies from all these industries, usually without treatment.

It is well known that textile mills consume large volume of water for various processes such as

sizing, desizing, scouring, bleaching, mercerizing, dyeing, printing, finishing and washing. Due to

the nature of various chemical processing of textiles, large volumes of wastewater with

numerous pollutants are discharged everyday.

In Bangladesh most of the industrial units are located along the banks of the rivers and they do

not use Effluent Treatment Plant (ETP) for wastewater. As a consequence, industrial units drain

effluent directly into the rivers without consideration of the environment.

Setup an effluent treatment plant is mandatory for a factory today. Authority gives no

permission of electricity and gas connection to a new factory without ETP.

ETP in Partex Denim:

Effluent Treatment Plant (ETP) of Partex Denim Ltd. has successfully established in the

beginning and running continuously 24 hours a day. They are maintaining all the discharged

parameters according to environmental law.

Figure: Effluent Treatment Plant (ETP)

PARTEX DENIM


Pag

e 16

5

Quantity:

The quantity of effluent to be treated shall be of the order of = 720 m3/day.

Capacity of the effluent treatment plant:

The effluent treatment plant has been designed on the basis of the following:

Ø Denim fabrics manufacturing plant.

Ø Contaminated effluent is 100%

Ø Less contaminated is nil

Ø Operated continuously for 24 hours a day

Ø Flow rate of treatment envisaged is 30m3/hr.

Inlet Effluent Parameters (General):

Flow Rate 30 m3/hr pH 8-14

BOD 400-600 PPM COD 1000-1200 PPM TSS 200-500 PPM TDS 3000-6000 PPM

Oil & Grease 30-60 PPM Colour Dark Mixed

Temperature 600C

Outlet Effluent Parameters (Bangladesh Standard):

Flow Rate 30 m3/hr pH 7-8

BOD < 50 PPM COD <250 PPM TSS <100 PPM TDS <2000 PPM

Oil & Grease <10 PPM Colour Clean

Temperature <300C

PARTEX DENIM


Pag

e 16

6

Process Flow Chart:

Screening

Equalization &

Skimming

Coagulation

Flocculation

Neutralization

Sedimentation

Biological Treatment Sludge Dewatering

Outlet to River/Drain Sludge Drying

Primary-Treatment

Pre-Treatment

Secondary-Treatment

Raw Effluent

PARTEX DENIM


Pag

e 16

7

11.2 Pre-Treatment

Screening:

The raw waste water (Raw Effluent) from the process of the plant would be first screened

through a manual bar screen strainer channel, where all particles with dia. > 5mm as well as

small pieces of the fibre and floating suspended matters like polythene paper, polythene bags,

rags and others materials removed by bar screen net. The bar screen consists of parallel rods or

bars and is also called a bar rack. These devices are used to protect downstream equipment

such as pumps, lines, valves etc. from damage and clogging by rags and other large objects. The

bar screen is cleaned manually by means of rakes. The screening is disposed off suitably after

they are de-watering. The screened clean effluent flows by gravity to an equalization tank.

Equalization and Skimming:

The raw waste water from the screen chamber is collected in the equalization tank, where it is

equalized with respect to its characteristics and homogenous flow and an uniform pollution

load as well as to make bacteria acclimatized the waste water is stored in a tank. High speed

bottom fixed aerating device which blows air through the waste at a rate about 0.1 CUF of air

per gallon of effluent. The rising air tends to coagulate the grease and oils and cause them to

rise to the surface where they can be removed by a scraper mechanism. Besides, in order to

accomplish a proper equalization of both varying loading and flocculating pH values. The

equalization tank is designed for hydraulic retention time of around 6 hours. A substantial part

of the COD will also be removed by the dissolved air flotation process.

11.3 Primary-Treatment

Coagulation & Flocculation:

The homogenized effluent is than pumped to a flash mixing tank followed by a flocculation

tank. Where added coagulants like lime (Calcium Hydroxide) and Ferrous Sulfate (FeSO4) for

coagulation of the total dye particles. The basic idea of adding coagulant is to bring together all

the suspended and dye particles so that they can precipitate out in a flash mixing and

coagulation mechanism. Adequate quantity of poly electrolyte polymer solution are dosed to

enhance the process of color removal by the flocculation process.

PARTEX DENIM


Pag

e 16

8

Precipitation and Sedimentations Tube Settler-1:

The flocculated effluent is taken by natural gravity in to the tube settler-1 from flocculation

tank for precipitation of dyes and suspended particles. The flocs formed are removed in the

downstream tube settler-1 by the help of tube settler media. The effluent will further flow by

overflow system to a pH correction tank where requisite quantity of acid will be dosed and pH

will be adjusted as per the requirement.

pH Correction:

The overflow effluent from tube settler-1 tank is than taken by gravity in to the pH correction

channel for neutralization. 33% HCl acid is dosed for neutralizing the pH from around 10 to 7.

The pH correction channel is designed for hydraulic retention time of around 10 minutes and is

provided with slow speed agitator for thoroughly mixing of waste with acid. A pH indicator is

installed in the tank for measuring the pH (optional).

11.4 Secondary-Treatment

Biological Reactor 1 & 2:

The neutralized effluent is taken by gravity in to the biological treatment aeration tank for

treatment of organic matter to reduce BOD/COD aerobically. The biological reactor is designed

on extended aeration principle. The aeration is provided with fixed type surface aerator for

providing the required oxygen for the biological degradation of BOD and COD. The air is

supplied by means of the bubble diffusion.

Figure: Biological Reactor

PARTEX DENIM


Pag

e 16

9

Tube Sattler- 2:

After aerobically treatment effluent flows by gravity to the tube settler – 2, the biological solids

generated are removed from the tube settler – 2 by the help of tube settler media.

Filter Feed Pump:

The effluent from tube settler – 2 overflow in to the pressure sand filter and activated carbon

filter feed pump. From here the disinfected effluent is pumped by means of the pressure sand

filter feed pump to the pressure sand filter. The pump is normally operated in automatically

with interlock to the level switch in the filter pump.

Pressure Sand Filter:

The effluent is pumped to the pressure sand filter. The filtration takes place in the downward

mode. The filter is filled with a layer of graded sand media supported by a layer of graded

gravel. The suspended matter in the effluent is filtered out in this unit, the effluent is then

flown into the activated carbon filter.

Activated Carbon Filter:

The filtered effluent from the pressure sand filter flows into the activated carbon filter. In this

unit to the feed flow is downward through a layer of granular activated carbon filter in which

dissolved organics in the effluent are absorbed.

Treated Effluent Tank:

The effluent emanating from the activated carbon filter is collected in the treated tank. From

this sump the final treated effluent is disposed off. As indicated before, this effluent is utilized

for backwashing the pressure sand filter and activated carbon filter units.

PARTEX DENIM


Pag

e 17

0

Sludge Treatment:

The sludge generated in tube settler-1, tube settler-2 and biological reactor is taken to a sludge

sump and pumped to a sludge thickener where sludge is concentrated. The thickened sludge

from the thickener shall be pumped to sludge drying bed for de-watering. The de-watered

sludge is formed into cake by natural dry or a centrifuge. The dried cake will be disposed in a

tank. The overflow from the sludge thickener will be flow back to equalization tank for further

treatment.

pH measurement experiment:

Due to our training period we performed an experience to measure the pH value before

treatment and after treatment and we found exact result from it. We measured the pH by using

pH paper and for the sake of clarity we instantly taken a picture of pH paper by a 14.1

megapixel digital camera. We cannot measure the others parameters due to unavailability of

instruments.

Discharge water value: pH 7.0-8.0 Raw effluent value: pH 11-12 pH scale

Sludge drying Sludge disposed tank Disposed sludge

PARTEX DENIM


Pag

e 17

1

Chapter Twelve

Maintenance

PARTEX DENIM


Pag

e 17

2

12.1 Introduction: Maintenance of machineries is very important for any type of industries and it is a must for all textile

mills. All machines and machine parts of spinning, weaving, knitting, dyeing and garments are

maintained with extreme care. Because production quality and quantity both are depends on the

maintenance with regularity.

Definition of Maintenance:

Maintenance is the action taken to prevent a device or component from failing or to repair normal

equipment degradation experienced with the operation of the device to keep it in proper working order.

Objectives/Advantages of Maintenance:

Ø To keep the factory plants, equipment, machine tool etc. in optimum working condition.

Ø To ensures accuracy of product & time schedule to delivery customers.

Ø To minimize downtime of machine.

Ø To prolong the useful life of factory plant & machine.

Ø To modify or improve productivity of existing machine to meet the need for production & thus

avoid sinking of additional capital.

Ø To improve the factory environment.

12.2 Types of Maintenance:

Maintenance can be classified as following way:

12.2.1 Reactive/Break-down Maintenance: Reactive maintenance is basically the “run it till it breaks” maintenance mode. No actions or efforts are

taken to maintain the equipment as the designer originally intended to ensure design life is reached.

Advantages:

Ø Low cost

Ø Less staff

Disadvantages:

Ø Increased cost due to unplanned downtime of equipment

PARTEX DENIM


Pag

e 17

3

Ø We are spending more dollars associated with capital cost because, while waiting for the

equipment to break, we are shortening the life of the equipment resulting in more frequent

replacement or repair.

Ø If it is a critical piece of equipment that needs to be back on line quickly, we will have to pay

maintenance overtime cost.

Ø Possible secondary equipment or process damage from equipment failure.

12.2.2 Preventive/Schedule Maintenance: Preventive maintenance can be define as action performed on a time or machine-run-based schedule

that detect, preclude or mitigate degradation of a component or system with the aim of sustaining or

extending its useful life time to an acceptable level.

Advantages:

Ø Increase component life cycle.

Ø Flexibility allows for the adjustment of maintenance periodicity

Ø Reduce equipment or process failure & estimated 12% to 18% cost saving over reactive

maintenance program.

Disadvantages:

Ø Labor intensive

Ø Includes performance of unneeded maintenance.

Ø Potential for incidental damage to components in conducting unneeded maintenance.

12.2.3 Predictive/Planned Maintenance: Predictive maintenance can be define as measurements that detect the degradation of machine,

thereby allowing casual stressore to be eliminated or controlled prior to any significant deterioration in

the component physical state. Results indicate current & future functional capability.

Basically, predictive maintenance differs from preventive maintenance by basing maintenance need on

the actual condition of the machine rather than on some preset schedule.

Advantages:

Ø Increased component operational life & availability.

Ø Allows preemptive corrective actions.

Ø Decrease in equipment or process downtime & estimated 8% to 12% cost saving over preventive

maintenance program.

Ø Better product quality.

Ø Improved worker & environmental safety.

PARTEX DENIM


Pag

e 17

4

Ø Decrease in cost for parts & labor.

Disadvantages:

Ø Increased investment in diagnostic equipment.

Ø Increased investment for proficient manpower & staff training.

Ø Saving potential not rapidly seen by management.

12.2.4 Capital Replacement: If it is seen that the repairing cost of machine parts is more or equal or little less than buying a new one,

then the old one is replaced instead of repair. It is known as capital replacement.

Maintenance Department of Partex Denim:

There is very active maintenance team in Partex Denim. Every group having a leader and two assistant

fitters. They all are very efficient and hard working. They can fix any type of mechanical problem of

machines. No necessity happens to hire others from outside to fix machine maintenance. There are

electro-mechanical groups to work for electrical problem of machineries. They work for overall factory.

Maintenance Procedure:

1. For there is any mechanical fault of machine which is responsible for production hamper,

operator informs mechanical fitters in duty. Mechanical fitters come and observe the problem

firstly, and then they begin to fix it.

2. If mechanical fitters be unable to fix it, then they inform technical in-charge, he then comes in

spot and fix it.

3. For there is any electrical problem of machine or serious founding mechanical problem,

mechanical and electrical department are informed, they come and fix the problem. They

commence at work after informing of production manager.

4. For restore active maintenance, senior production officer orders mechanical fitters to fit

required machine.

PARTEX DENIM


Pag

e 17

5

Cleaning Types:

Section Cleaning

Warping Every day (by air)

Dyeing Every shade change ( by water)

Weaving Every day (by air)

Finishing In a week/month (by water)

Oiling & Greasing of Weaving Machine:

Name Brand Area Quantity Amount

ISO 150 Mobil Airjetcentre box 27 liters/loom One drum= 208 L VG 220 Mobil Rapier centre box 27 liters/loom One drum= 208 L ISO 320 Mobil All cam box 7 liters/loom One drum= 208 L RARUS 425 Mobil Knotting m/c Every 90 days/drum/mc One drum= 20 L EP 2 Mobil All m/c (Grease) 120 Kg/month for 168 looms One drum= 180 Kg PG 75 Molykote Leno holder 01 Kg/week for 132 airjet looms 01 pcs = 01 Kg

12.3 Functions/Elements of Maintenance Department: Following are some important functions of maintenance department:

Inspection or check-ups:

Ø Crews kept for inspection should be well trained.

Ø External inspection means to detect from abnormal sound, vibration, heat, smoke etc.

Ø Internal inspection means to check internal parts of the machine.

Lubrication:

Ø Systematic lubrication means the application of right type of lubricant at right time at right place

& in right quantity.

Ø It is done to minimize friction & reduce decay of machine parts.

PARTEX DENIM


Pag

e 17

6

Planning & analysis:

Ø Every preventive maintenance work should be pre-planned.

Ø The program is specified in detail by mentioning daily, weekly & yearly attention.

Records & analysis:

Following records are generally maintained:

• Operational manual

• Maintenance instruction manual

• History cards & history register

• Inspection register

• Log books

• Defects register etc.

Training of maintenance personnel:

The technicians & supervisors of maintenance department should be well trained in a systematic way.

Storage of spare parts:

In is essential to store some essential spare parts which are needed every now & to keep the machine

running & reduce stoppage time for machine defects.

12.4 Requirements for Good Maintenance: Ø Good supervision & administration of maintenance department.

Ø Operators should be well trained.

Ø Proper maintenance record should be maintained.

Ø Adequate stock of spare parts should always be kept.

Ø Manufacture of the machine tools should be consulted as & when required.

Ø Maintenance department should remain in contact with planning & purchasing department

deciding the type of machine tools to be purchased.

PARTEX DENIM


Pag

e 17

7

Chapter Thirteen

Store & Inventory Control

PARTEX DENIM


Pag

e 17

8

Store and Inventory Control:

Inventory control of raw materials, semi-finished goods, finished goods and other

miscellaneous goods lead smooth production. As Partex Denim Ltd. follow the correct way of

inventory control system, it can have a good and huge production as it demands.

There are two (one is small & other huge) room for storing and inventory control.

Scope of inventory control:

Ø Raw materials

• Yarns

• Dyes store

• Others chemicals store

Ø Finished fabric

Ø Spare parts

Ø General store

Ø Capital equipment

Ø Accessories

Ø Stationary

Ø Maintenance parts.

Inventory System for Raw Material:

The main raw material of denim fabric is yarn, which is stored in two stages such as-

1. Long time storage

2. Storage before production

1. Long time storage:

Amount of yarns which are required for the production of several months as prerequisite.

2. Storage before production:

The amounts of yarn, which are loaded in the store, room concern with the production section

for continuous speed of production.

PARTEX DENIM


Pag

e 17

9

Inventory System of Spare Parts:

The spare parts of different section such as preparatory & dyeing, weaving section, finishing

section are stored. If a machine is innovated its slightly effected parts will be stored as spare

after repairing needed. In addition, these parts are used in conjunction with new parts.

Inventory Control of Finished Goods:

After the completion of finishing, the finished fabric is stored from where the finished fabric is

delivered to the buyer.

Other Inventories:

Other inventories like empty packages or packages with few yarns & cartoons are stored in

wastage room. From this, packages with few yarns are used for sample production. Mechanical

equipments for maintenance are stored in mechanical room, lubricants are stored in lubricant

room & a drum is kept in the shed as stand by requirement.

PARTEX DENIM


Pag

e 18

0

Chapter Fourteen

Marketing Activities

PARTEX DENIM


Pag

e 18

1

Marketing Activities:

The commercial section of Partex Denim Limited performs the following functions:

Ø Official dealing with buyer

Ø Communicate with factory in charge for issuing delivery date

Ø Dealing with bank

Ø Preparing different necessary documents

Procedure of Export Business by Partex Denim:

To get order:

Like any other factory, Partex do not need to any kind of product marketing to get order. It is so

much renowned denim factory in Bangladesh that they do not knock the buyer's door for order.

Buyers come here with query for definite sample or style for their own interest.

Sample preparation:

Partex denim already prepared over five thousand types of fabric sample. So they have huge

number of fabric sample collection. If buyer's requirement match with any of earlier fabric then

a sample from stock is send to them, otherwise a new sample is prepared and sends to buyer.

Issuing of P.I (Performa invoice):

If the buyer approves the sample, then Partex issues Performa invoice to the buyer.

What is P.I. (Performa Invoice)?

Performa invoice is a paper where all the terms and condition of that business dealing is write

down. Partex mainly notice the following points in their PI:

Ø Description of the product.

Ø Price

Ø Last date of L.C open 'by the buyer

Ø Date of delivery

Ø Date for bill payment after delivery

PARTEX DENIM


Pag

e 18

2

Ø Some other official terms and condition

L.C. (Letter of credit) opens by the buyer:

If the buyer agrees with the terms and condition on the P.I then the buyer open L.C against that

order.

What is L.C (Letter of Credit)?

L/C (Letter of Credit) is credit contract whereby the buyer's bank is committed (on behalf of

buyer) to place an agreed amount of money at solicits disposal under some agreed condition.

PARTEX DENIM


Pag

e 18

3

Chapter Fifteen

Security

PARTEX DENIM


Pag

e 18

4

Security Section:

The main objective of the security is to safe handling of the goods from/to the mill premises. For the

achievement of such objective a team of security guards has been employed by the Company. All the

keys relating to the mills office, labor colony, (quarters) are lying into the responsibility of the security

officer.

No outside visitor can come into the mills premises without the permission of the security guards or

administration department.Whenever any visitor wants to enter the mills, security guard firstly contact

with the authority in the mills to grant the permission to enter into the mills premises.

Security guards check each and every person before coming in or going out of the Company gate for the

security purposes.They have certain uniform of brown shirt and brown pent. They are the guardian of

everything of the Company.

Security Main Gate:

Ø This office has been made to keep the record of each and every thing coming into and going out

of the mills gate.

Ø This office keeps and maintains the time record of all the workers on time cards and pay register

for the final costing of the workers’ salaries.

Ø It keeps the attendance records, which is then used to calculate the salary to be paid to the

workers on monthly basis.

Ø It keeps the records of the overtime, leaves, number of days worked of all the workers and then

calculate their overtime on the basis of the basic salary of each worker.

For 24 hours close attention to the production floor and also the outside, there are several close circuit

camera all over the factory. This operation is done by the administration department from

administration office.

PARTEX DENIM


Pag

e18

5

Security Post:

This image taken from goole earth showing direct sallellite picture of the factory to understanding the secutiry post all over the factory. Black

circle shows security post and Red circle is the main gate of the factory.

PARTEX DENIM


Pag

e 18

6

Chapter Sixteen

Quality Assurance

PARTEX DENIM


Pag

e 18

7

Quality Assurance in Denim

Denim has gained much popularity that if you look around, you will surely notice somebody wearing

denim in your nearby. Now, more than just complementing a rugged style, the denim has become

suitable for any occasion. Denim is being worn irrespective of demographic differences. The material

denim is synonymous with familiar blue jeans and is denoted by a rugged twill textile that produces the

familiar diagonal ribbing. Today, there are around twenty Denim manufacturers in Bangladesh alone

catering to the domestic and export markets. The manufacturing facilities are fast catching up at India,

Pakistan and Vietnam. Denim today is now available in various shades of blue, black and brown within

each there are different effects generated by washing.

As Denim is a competitive market product, there will always be pressure on price and quality. One can

gain upper hand in pricing if their manufacturing cost is low. One of the ways of reducing the

manufacturing cost is reducing the raw material cost, reducing the production losses and reducing the

second's generation.

Quality Assurance in Denim mill can thus significantly help in achieving the above objectives.

Academically, Quality Assurance may be defined as "the planned and systematic activities implemented

in a system for fulfilling the quality requirements of a product or service." The current paper highlights in

brief various check points employed in Denim mill for arresting the non-conformities so as to reduce the

production losses and quality down gradations.

Technical Specifications:

The following guidelines can be followed at each stage starting from raw material selection to dispatch

of denim fabrics:

1. Handling of Raw materials in Godown:

Basic raw material for denim fabric is yarn. The same is either produced internally or is procured from

outside. Following care should be taken for avoiding the damage of packages in go down:

Ø In case of yarns purchased from outside, yarn should be unloaded from truck gently and location

of godown should be as near to warping. This will ensure minimum yarn damage due to impact

and significantly improve the warping performance due to reduction in cut ends.

Ø In case of In-house yarn, plastic packages are used generally. Car needs to be taken to use

undamaged plastic packages only so as to minimize breaks at warping due to worn out

packages.

PARTEX DENIM


Pag

e 18

8

2. Approval of raw material:

The raw material for composite Denim mill is fibre while for non composite mill it is yarn only. The raw

material should be approved first before consuming for production. Following raw material parameters

effect the yarn properties and running performance.

For any new supplier/yarn sample it is always better to test the same by running the yarn as weft in the

running looms for assessing its performance.

Slub yarn approval should be given only after assessing the appearance either on yarn appearance board

or by producing the fabric by running the same on the loom along with standard Slub yarn.

3. Warping:

Warping serves as the acid test for the assessing the yarn quality. Warping performance is considered to

be satisfactory if breaks/million metre at 1200 mpm is as under:

Following points should be taken care while warping for getting the lower end breakage rate:

Ø Damaged package found while mounting should not be creeled.

Ø Tension in the yarn should be adjusted so that yarn sheet is neither slack nor very tight (Norm is

10% of the yarn breaking strength).

Ø High speed provides necessary tension to the yarn sheet. In case of higher breaks speeds can be

reduced to some extent. Drum pressure should be selected based on the hardness required of

the warpers beam.

Ø The warpers beam rims (flanges) should be checked periodically for damage and eccentricity.

Ø The breakages should be recorded along with the reason like cut ends, breakage from Slub,

opening of splice portion so as to take corrective action for next supply.

PARTEX DENIM


Pag

e 18

9

4. Dyeing & Sizing:

It has been found that yarn performing very good at warping sometimes create problem at dyeing range

due to greater liveliness leading to grouping of yarn. Sometimes yarn performing poorly at warping leads

to good running at dyeing. This may be due to elimination of all weak points at warping itself. In addition

to performance concerns, shade consistency and centre side variation is also one of the challenges for

mills having sheet dyeing ranges. These challenges make dyeing and sizing as very important operations

in the Denim manufacturing. Following points should be taken care while dyeing & sizing:

Ø Alignment of warpers beam in creel should be perfect.

Ø In India most of the milis are using indigo in powder form only. Thus purity, moisture content

and tone (reddish/greenish) of indigo powder must be checked before taking in bulk production.

Ø The parameters like pH & mV of the dye liquor needs to be checked every 30 to 45 minutes.

Generally it is kept around 11.5 to 12.0 and 750 ± 30 respectively. In many advanced machines,

online checking & display of these parameters is also available.

Ø For shade consistency, yarn should be drawn from every beam for shade evaluation manually as

well as by spectrophotometer.

Ø Mills facing Center Side Variation should draw yarns from both the sides and centre from front

of the dyeing machine and check for any variation Size add on is generally kept around 8 to 12%

depending on yarn count.

Ø Solid content or Rf % is generally kept around 8.5 to 14 % depending on yarn count.

Ø Moisture in sized beam should be around 7 to 8% so as to get better loom performance.

Ø Sized yarn should be tested for checking the increase in strength and loss in Elongation.

Generally yarn strength is increased by 25% and yarn elongation is dropped by 20%. In any case

yarn elongation of sized yarn should be above 3.0% for better loom efficiency Excellent work

practices should be adopted for cutting the lappers and attending breaks in dry splitting zones

so as to minimize yarn cross ends/missing ends so as to get better performance in weaving.

5. Weaving:

Weaving is an operation where first image of denim fabric is realized. On getting perfect beams, the

weaving efficiencies generally reaches Y6 to 98% per shift. In general the performance is considered

satisfactory till Warp and Weft break level is less than 1.5 breaks/ cmpx. Following points should be

taken care while weaving so as to supply defect free material to the next operation.

Ø Weft yarn should be kept covered with plastics / cardboards so that no fly gets deposited on the

packages.

Ø Care should be taken while beam knotting so as to avoid any crossed ends.

Ø High speed air jet looms are commonly used for weaving denim fabrics. Air pressure should be

adjusted perfectly depending on the weft so that weft passes smoothly through the shed

without creating defect like furkey.

PARTEX DENIM


Pag

e 19

0

6. Singeing:

Singeing is an important operation as it burns the protruding fibres from the fabric surface. Following

care needs to be taken while singeing:

Ø Flame quality should be perfect (singeing should be done in blue flame only).

Ø Flame height should be uniform (4 to 5 inches) and should not vary throughout the width else it

will lead to bands in the fabric.

Ø Speed should be optimum (around 70 to 80 mpm) so that effective singeing action is performed.

7. Finishing:

In denims two types of finishing machines (Foam finish/Wet finish) are found. Both have it's own

advantages and disadvantages. Irrespective of the type of finishing machines, following points should be

taken care while finishing operation:

Ø The greige fabric must be tested for knowing the shrinkage & skew potential.

Ø Based on the shrinkage & skew potential, shrinkage & skew is applied so that residual shrinkage

in fabric is less than 3.0% and skew movement less than 2.0%.

Ø The fabric entering Sanforiser should be moist (around 12 to 1 5%) in order to get good body. I n

absence of moist fabric, the fabric feel is very limpy. Nowadays online moisture meter are also

installed in the region for monitoring of same.

Ø The draft between sanforiser and palmer cylinder should be less than 1.0% so that shrinkage

applied is not lost due to stretching.

Ø The finished fabric should be checked for all properties like weight, shrinkage, skew, stiffness,

tensile and tear strength before releasing to inspection department.

8. Inspection & Packing:

Inspection provides the true picture of the fabric quality by informing the main defects for down

gradation. Action can be taken in particular department for reducing the value losses. Following steps to

be taken in inspection and packing department for getting the right quality product:

Ø Inspection to be done for 100% fabric by any accepted inspection system. In general 4 point

inspection system is commonly followed.

Ø Full width fabric sample of 10" length from every roll is collected for pick checking and shade

grouping.

Ø Full width sample after every 4000m should be sent to laboratory for parameter testing like

weight, shrinkage, skew, stiffness, tensile and tear strength.

Ø Paper tube length & quality should be perfect so that fabric doesn't hang from the edges and

paper tube doesn't get collapsed during storage or transit.

PARTEX DENIM


Pag

e 19

1

Ø Each fabric roll is weighed and packed using HOPE woven cloth, shrink wrapping or stretch

wrapping Fabric weight (OSY) should be checked from length and weight of the roll before

dispatching so as to segregate lower weight rolls if any.

9. Washing and shade grouping:

Washing and shade grouping is very important activity in Denim mill. Export buyers or very reputed

domestic buyers ask for the taper/sequencing report along with the dispatches. Generally buyers ask for

the washed swatches along with taper/sequencing reports. The important point is as under:

Ø The collected 10" sample from every roll is cut into five equal pieces. One piece from all the rolls

of the particular order are stitched as blanket along with standard swatch and washed as per the

customer recipe or own developed recipe. After washing the swatches are measured on

spectrophotometer for shade values and off shade rolls are removed from the dispatches. In

case of major shade off, recipe of washing can be changed (if acceptable to customer) and same

should be communicated to customer for getting the desired shade as required.

Ø 10 Storing of Rolls Storing in godown is all together a specialized activity. If not done properly all

the good work done so far will be no use. In general, care should be taken for following points;

§ Rolls should be stacked horizontally and not vertically. Vertical stacking lead to waviness

problem on opening.

§ Rolls should be stacked in such a way that it is easy to locate any roll at the time of

dispatch.

10. Dispatch:

Dispatch is last activity but certainly but very important. Following care needs to be taken during

dispatch operation:

Ø Care should be taken the approved roll list given by QA is only loaded Loading should be gentle

enough so that there are no damage to the packing

Conclusion:

From the above it is clear that each and every operation is important and contributes significantly to the

quality of the product. One should arrest the non-conformity where it happened so that further

operation is not affected. This way production loss is minimized and product produced is of superior

quality.

PARTEX DENIM


Pag

e 19

2

Discussion

Partex Denim Ltd. is the largest and most versatile business conglomerate in the private denim

sector in Bangladesh. Partex Denim Ltd. is committed to the best human workplace practices.

Their goal is to continuously improve their Human resource policies and procedures

through education, training, communication and employees involvement. Right from inception

the policy of the company has been to provide total customer satisfaction by offering quality

denim fabric in time. To meet the manufacturing to quality and promote delivery Partex Denim

Ltd. decided to integrate the manufacturing process in a planned manner. Over the year the

entire process has been integrated by importing sophisticated machinery from world renowned

manufacturers. According to their capacity they have an enriched production team which is

very rare in other factories of Bangladesh. The working environment of Partex Denim Ltd. is

very cordially & friendly. All of the executives & employees of Partex Denim Ltd. are very much

cordial & they always appreciate the learners.

The goal of Partex Denim Ltd. is to get high production & to maintain the quality of the product

at a minimum cost.

Some suggestions:

The warping floor is dirty most of the time though it is cleaning every day. Fly dust removed

from yarn surface create this problem. Necessary steps should be taken for keep better

cleaning condition all the time because warping section situated at the front side of Main gate.

Cleaning environment will increase better satisfaction to buyers.

Ø The upper shed of the factory floor is a little bit broken/leakage in some places which

causes water fall when raining.

Ø The temperature of the sizing shed is higher than others though it has ventilation

system. We think blower fan’s speed should increase for better suction of hot air.

Ø There is no overhauling maintenance for few machines. We think overhauling

maintenance should carry on by maintenance department for continuous production of

machines.

Ø Unnecessary lighting should remove for less power consumption.

Ø There is no conference room for workers training. We think workers training can

improve the total production system and also the profit. So a conference room should

establish.

PARTEX DENIM


Pag

e 19

3

Ø There is no identity card for officers. I think this is very important for security system

and also for advertising.

Limitations of the report:

Ø I had a very limited time. In spite of our willing to study more details it was not possible

to do so.

Ø Some of the points in different chapter are not described as these were not available.

Ø The whole process is not possible to bind in such a small frame as this report, hence our

effort spent on summarizing them.

Conclusion

I have completed my industrial attachment successfully by the grace of Allah. Industrial

attachment sends me to the expected destiny of practical life. Though it was established only a

few years ago, it has earned “very good reputations” for its best performance over many other

export oriented textile mills.

During my training period, talking with the clients of this mill I knew that the mill is fulfilling the

country’s best export oriented finished fabric as well as very good quality fabric due to its

modern machinery & good management system.

Mill is settled with utility to give all convenient supports to the productions for twenty-

four hours. It had self-power generator system to satisfy total power consumptions of the mill.

I am enough fortunate that I have got an opportunity of having a training in this mill. During the

training period I have received co-operation and association from the authority full & found all

man, machines & materials on appreciable working condition. All stuffs & officers were very

sincere & devoted their duties to achieve their goal.

Finally I would like to wish Partex Denim Ltd. to have a blast & thanks to administration of

Partex Denim Ltd. for their cordial attitude to me.

PARTEX DENIM


Pag

e 19

4

References:

1. http://www.partexholdings.com/index.html

2. http://www.partexdenim.com/

3. http://maps.google.com/maps?hl=en&tab=wl

4. http://morrisontexmach.com/welcome.cfm

5. http://www.denimsandjeans.com/

6. http://articles.fibre2fashion.com/

7. http://www.picanol.be/PICBESITE/EN/

8. http://www.cibitex.it/_eng/home.asp

9. http://www.sttm.com.tw/e_index2.html

10. http://www.ngaishinghk.com/english/products/industrialWashing.htm

11. http://www.mechmar.com.my/products_as.htm

12. http://www.dresserwaukesha.com/index.cfm/go/list-prodsubline/productline/gas-

compression-engine/

13. http://us.kaeser.com/Products_and_Solutions/Compressed-air-treatment/default.asp

14. http://www.lsaircondition.com/lsgonjo_eng/default.asp

15. http://spacco.com/documents/25.html

16. http://www.aesa-ae.com/en/textile-air-engineering/

Partex Denim_Israfil Alam Rana

Documents

Transcript of Partex Denim_Israfil Alam Rana