Design & Implementation of Productivity Measurement System in Fabrication Department

7/22/2019 Design & Implementation of Productivity Measurement System in Fabrication Department

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KONKAN GYANPEETH

COLLEGE OF ENGINEERING, KARJAT

CERTIFICATE

This is to certify that the Mr. KAUSTUBH VINAY KOKANE has successfully

carried out the project entitled IMPLEMENTATION OF PRODUCTIVITY

MEASUREMENT SYSTEM IN FABRICATION DEPARTMENT during semester VII

in partial fulfillment of Bachelor of Engineering in Production Engineering degree

awarded by the Mumbai University in the academic year 2011-2012.

Prof. V. K. Gajare Mr. Vasuki P. H. Mr. S. S. Agarkar

(College Guide) (HOD, Fabrication-19) (Company Guide &

GM- Manufacturing)


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SYNOPSIS

NAME OF COLLEGE : Konkan Gyanpeeth College of Engineering,

Karjat

CLASS : B.E. (PRODUCTION)

SEMESTER : VII (REVISED)

ACADEMIC YEAR : 2011-2012

PROJECT TITLE : DESIGN & IMPLEMENTATION OF

PRODUCTIVITY MEASUREMENT SYSTEM IN

FABRICATION DEPARTMENT


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ACKNOWLEDGEMENT

On successful completion of my 7th semester in-plant training at Godrej & Boyce

Mfg. Co. Ltd., I take this opportunity to convey my profound gratitude to all concerned

people who have helped me.

It is only befitting, that I first thank our college management and respected Principal

Mr. M. B. Lele, our H.O.D. Mr. A. G. Nagpure, Training & Placement in-charge Mr. S. R.

Shastri & my project guide Mr. V. K. Gajare for arranging this in-plant training.

I thank Mr. Uday Deshmane (Training & placement officer, Godrej) for giving me an

opportunity to work in the PES division at Godrej Vikhroli establishment.

I am indebted to my company guide Mr. S. S. Agarkar, Mr. Vasuki P. H. and Mr. S.

B. Nuchu for their valuable guidance and support throughout my training period. I would

also like to express my heartfelt gratitude to Mr.Biswadeep S Biswas, Mr. Amit R. Panchal,

Mr. Navaj A. Sattar, Mr. Alam Khan and Mr. Prashant Warudkar for their full

encouragement & guidance throughout my training period.

It would be inequitable if I disregard the co-operation of Quality Assurance, Design,

M.P.C., Machine Shop, Maintenance, Paint Shop and Assembly departments for showing me

how teamwork is done in our PES plant.

Finally, though not the last, I would like to thank all the workmen for their constant

co-operation, support and generous information regarding all the operations that are carried

out at shop floor-level. They were a source of real-life knowledge for me, which I couldn't

have grasped from any textbook.

KAUSTUBH V. KOKANE


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INDEX

CHAPTER

NO.DESCRIPTION

PAGE

NO.

1 Company Profile 8-12

2 Introduction to PES Division 13-20

3 Introduction to Fabrication Department 21-24

PROJECT

DESIGN & IMPLEMENTATION OF PRODUCTIVITY

MEASUREMENT SYSTEM IN FABRICATION

DEPARTMENT

25

4

Literature Survey

26-31

5.1 Definitions of Productivity

5.2 Partial Productivity

5.3 Welding Productivity

5.4 Factors Affecting Welding Productivity

5.5 Difficulties in Measuring Productivity

5

Workstation Productivity Measurement

32-416.1 Productivity Analysis of Workstations

6.4 Workstation-wise Analysis & Justification

6

Productivity Measurement by VA-NVA Analysis

42-54

7.1 VA-NVA Analysis

7.2 Standardisation of VA-NVA Activities

7.3 Time Study7.4 Job-specific VA NVA Analysis by Time Study

7.6 Summary Analysis

7.7 Important Improvements

7

Loss Analysis

55-608.1 Sixteen Major Losses

8.2 Job-specific Loss Analysis

8

Calandria Stage I Welding Productivity Measurement

61-70

9.1 Methodology

9.2 Test to Determine Weld Deposition

9.3 Welder Efficiency & Productivity

9.4 Parameter Monitoring

9.5 Theoretical vs. Actual Parameter Comparison9.6 Consistency Trend Analysis

ASSIGN-

MENT

DESIGN & IMPLEMENTATION OF WATER COOLING

ARRANGEMENT FOR CALANDRIA STAGE I NOZZLES71-74


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COMPANY PROFILE

Godrej Industrial Township- Pirojshanagar, Vikhroli

From high tech engineering solutions to daily-use products like locks, Godrej has touched lives

of millions of Indians since it was found in 1897 by an ambitious visionary, Mr. Ardeshir Burjojee

Godrej. After 115 years, Godrej has turned into a conglomerate worth US$ 2.6 billion spreading its arms

globally.

Recent change in brand identity further helped grow the brand. Enriching the Quality of

Life..Everyday, Everywhere is the mission of Godrej group, which signifies the involvement and

importance of Godrej products in Indian peoples lives.

Today Godrej employee over 15,000 people and has grown into one of the most trusted brands in

Indian industry with far reaching service and distribution network. The companys corporate head officeand a huge industrial township is located at Pirojshanagar, Vikhroli, The brainchild of Ardeshir Godrej

has turned into a pioneer for Indian private industries. As it strides ahead confidently, it gives direction to

others.


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VIKHROLI ESTABLISHMENT-

After acquiring vast land of 3200 acres in Vikhroli in 1948, Godrej group has developed it

seamlessly turning it into a benchmark company campus.

Godrej & Boyce is truly a multi-faceted private enterprise housing the following manufacturing

plants in its Vikhroli campus.

PLANT DIVISION & PRODUCTS/SERVICES

1 Steel & Other products manufacturing plant-

-Architectural fabrications, ERW Tubes, feeder of cut steel to other plants.

2,3,5 Godrej Appliances

-Production of Refrigerators, Washing Machines, Microwaves, DVD players

and Air Conditioners

4 Office Equipment Division, Furniture Manufacturing Division

- Production of Office Furniture, Seating and Desk Systems, Computer Furniture

and Home Furniture, Home Storewels, Filing Cabinets and Filing Systems,

Sliding/Tambour Door Units, Personal/Industrial Lockers, Customized storage

Systems, Roll-formed Slides and Components for Furniture

7,8 Tool Room Division

- Production of Precision Tooling (Press Tools / Plastic Injection Moulds / Vacuum

Forming Moulds / Pressure Die-Casting Dies), Special Purpose Machines, High

Precision Components / Equipment for Engineering and allied industries, Sheet

Metal Working


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Godrej & Boyce Group Structure


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MAJOR PROJECTS UNDERTAKEN AT PES, PL-19

F/M Bridge & Carriage-

Bridge & Carriage Assembly

Project overview-

This assembly acts as the drive mechanism for TAPP and KAPP nuclear power plants operated

by NPCIL. These mechanisms are used in Level 1 safety area of reactor to raise and lower the shut off

rods in reaction chamber.

Important characteristics-

Material SA 515

Size- 9600 x 1100 x 12500 (height) mm

Weight- 70 tons

300 components per assembly

Flatness requirement of 50 microns over 1600 x 8000 mm surface

Challenging task of alignment 10 meter long columns


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Wind Turbine Parts for Enercon India Ltd-

Enercon project components

Project overview-

Enercon India is aiming to create a nation-wide network of wind-energy operated power plants.

These windmills are located in deep seas or on land where average wind speed is high.

The three components of a windmills manufactured at Godrej PES are extremely vital to itsfunction.

Important Characteristics-

3 Components of CS of 4m diameter, each weighing about 3 tons

Fabrication of a combination of prismatic and cylindrical sections to accuracies of +/- 1mm over

4m length

Fabrication of equipment i.e. prone to heavy distortion during welding

Special fixtures- pneumatic and mechanical fixtures to avoid distortion

Extensive use of automatic welding processes- FCAW and SAW


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Calandria-

Position 1 Position 2

Project overview-

Calandria is the heart of a nuclear reactor. It is the chamber which holds the radioactive fuel rods

when nuclear fission is occurring. Fuel handling mechanism is also commissioned along with Calandria

to handle new or spent fuel rods.

This particular unit of Calandria is being manufactured for the NPCIL-operated Kota Atomic

Power Plant (KAPP), Rajasthan.

Important characteristics-

Requires a separate enclosure for fabrication to avoid contamination and any contact with CS

material

Total 122 nozzles to be welded in 5 stages.

Automation of plasma cutting process to achieve maximum accuracy Involves GTAW welding in 6G position

Transportation to site (KAPP, Rajasthan) by road is a challenging task.


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Departments in PES

PERSONNEL:Personnel department is the HR-arm of PES division. It handles all manpower related issues and

handles all contractors on behalf of the manufacturing units. Plant Manager and Time Keeper are the two

persons representing Personnel department in every plant.

Apart from all HR related activities, the personnel department also handles the attendance related

issues of all employees, workmen, trainees and apprentices.

MARKETING:

Marketing department is one of the most important departments involved in the cycle of a

product. Even though it is not directly involved in manufacturing activities in any way, it is the reasonwhy manufacturing units receive the order in the first place.

Marketing department seeks orders from suitable sectors by participating in bids from different

companies. Further, important strategic decisions like choosing the most appropriate project to bid for are

all taken by marketing department after consulting with respective manufacturing departments.

DESIGN:

At Godrej, stress is on using internal drawings for uniformity and ease of understanding. This is

where the Design department plays its role. A team of experienced designers with individual CAD

stations works closely with customers to understand their requirements and make uniform-standard

drawings available for manufacturing.

The team uses the most advanced software in the industry including Inventor, AutoCAD and

Ansys. 3D models of intricate components are also made available for precise manufacturing.

PLANNING:

Planning department is the think-tank behind all routing, sourcing and logistics activities. All

important activities from deciding the raw material supplier to transporting medium are done by planning

department. Project planner decides the sequences of operations and supplies job cards along with

project drawings to the respective manufacturing teams.

Planning department employees are involved in the manufacturing cycle of all projects right

through marketing activities to final dispatch of the manufactured job.


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MANUFACTURING:

FABRICATION:

After receiving raw material from Material Preparation Cell (M.P.C.), Fabrication department

and its 130-strong force of experienced workmen consisting of welders, grinders and fitters that

team up to carry out actual value-added manufacturing activities.

Welding methods used in Fabrication department include FCAW, SMAW, GTAW and SAW.

Welding automation is also encouraged by fabrication supervisors wherever possible, as it reduces

the cycle time considerably and improves the quality of weld produced. Special enclosure is also

available in Plant-19 for SS fabrication when contact with CS material is to be avoided.

MACHINE SHOP:

After being released by Fabrication department, Machine Shop takes over the job and precision

machining is carried out with state-of-art machines. AC enclosure is also available for precisionmachining of small components. CNC machining with up to 1 micron accuracy can be achieved at

PES Machine Shop.

ASSEMBLY:

Assembly department takes over the job in final stages of its manufacturing cycle at Godrej PES

division. Plant-19 houses a shot blasting booth and two paint booths which are operated by

Assembly department. Highly precise assemblies are made with help of special fixtures and an

experienced & skilled workforce.

Currently, a 2.5m deep crater is being dug in Plant-19 for the final assembly of Bridge &

Carriage job before dispatch.

QUALITY ASSURANCE & INSPECTION:

Although the QA department doesnt carry out any manufacturing activities, it ensures that the

job stays within required tolerance limits and accuracy expectations are met at all times. Engineers are

trained in different NDT techniques such as LPT, UT, MPI and RT.

MAINTENANCE:

This department takes care of all the machines in the plant. It looks after the daily maintenance

like checking the lubrication etc. It also undertakes preventive maintenance foe increasing the efficiency

of the plant.


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INTRODUCTION OF FABRICATION DEPARTMENT

PES division is housed in both Plant-9 and Plant-19 with two separate fabrication shops. Carbon

Steel jobs weighing more than 20 tons are fabricated in Plant-19 and smaller jobs where higher degree of

precision is required are fabricated in Plant-9. There is a separate enclosure for stainless shell fabrication

in Plant-19, where currently Calandria is housed.

Three main pillars of fabrication department are as follows-

1) Training-Comprehensive training is given to all staff and workmen in order to provide them with

operational knowledge related to their work. Different types of trainings provided to workers are as

follows-

i.Apprentice Training-Learning apprentices undergo trade-based training in order to provide them with in-depth

knowledge of their respective trades and different operations related to their trades.

ii.Trade Training-

Periodic trade training is provided to all workmen to further improve their knowledge and

share any new developments related to their trades. Also, in case any new machines are

commissioned in Plant-19, Fabrication, all respective operators are provided extensive training

on the functions of machine.

iii. Safety Training-Regular safety training and meetings are held in order to discuss the ways of improving

safety scenario on shop floor and safe practices of operation.

iv. Multi-skilling-It is a creative new initiative undertaken by PES where workers are trained in trades other

than their own. The main purpose of such training is to reduce the overall cycle time and labor

cost.


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Project

DESIGN & IMPLEMENTATION OF

PRODUCTIVITY MEASUREMENT SYSTEM

IN

FABRICATION DEPARTMENT


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LITERATURE SURVEY-

DEFINITIONS OF PRODUCTIVITY-

It is difficult to define productivity in standard terms as the phenomenon varies with change in

field of use. For example, the productivity norm used in manufacturing industry can not be used in

construction industry. Thus, it is very important to focus on the factors that are quantifiable and can yield

an interpretable and clear picture of the productivity scenario.

Productivity signifies the measurement of how well an individual entity uses its resources to

produce outputs from inputs. But, selection of factors to be measured is tricky. In general, productivity

can be defined as 'rate of output'. Input and output may vary but at the end, productivity is always a 'rate'

(ratio) of output and input quantities.

The above definition can also be stated as a measure of efficiency of production.

Productivity= Output Quantity

Input Quantity

When the work being done is not exactly quantifiable, it is difficult to measure its productivity in

statistical terms as there is no empirical formula which can help us measure working productivity.

In practice, quantitative and qualitative changes take place when relative quantities and relativeprices of different input and output factors alter. In order to accentuate qualitative changes in output and

input, the formula of total productivity shall be written as follows

Productivity= Output quality and quantity

Input quality and quantity

In manufacturing industry though, the work done on shop floor is in quantifiable terms. Accurate

monitoring of different parameters related to any processes in the shop will help us get a clear picture of

productivity scenario. But, the same is not true for purely manual processes (e. g. SMAW welding).


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WELDING PRODUCTIVITY-

Benchmarks for welding productivity are not yet implemented properly in any frontline Indian

manufacturing company. Benchmarks for welding productivity may differ from company to company

based on availability of skilled workforce and hence, it is very difficult to compare the productivitystandards of two organisations. On the other hand, the same productivity measurement systems are

considerably clearer in the western countries like the U.S.

According to a survey by the Department of Commerce, U.S., leading industries use the

following eight general welding productivity measures-

1) Welding speed- (e.g. mm length welded per period of time)

2) Welding process output (e.g. Joint completed per period of time)

3) Welding deposition rate (e.g. kgs of weld metal deposited per period of time)

4) Welding machine arc time (% of time welding machine is in operation)

5) Welded product output- Standardized product- (e.g. welded components completed per period of

time)

6) Welded product output- Customized product- (e.g. tons of steel joined per period of time)

7) Welding defect rate (e.g. defects per 100 welds completed)

8) Performance versus time standard (e.g. percentage of production completed within specified time

standard)

Use of multiple productivity measurement standards is recommended as gives more precise estimate

of welder productivity.

At PES, Plant-19, we use the following productivity measures-

1)

Welding speed2) Welding deposition rate

3) Welding defect rate (defects in terms of % weld length)

4) Performance versus time standard


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IDLE TIME ANALYSIS-64% idle time recorded was further sorted by its root causes-

1) No job

2) No manpower (No workers)

3) Waiting for instructions4) Machine breakdown

5) Start-up losses

6) Miscellaneous Losses


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STANDARDISATION OF VA-NVA ACTIVITIES-

Before carrying out a detailed analysis regarding VA-NVA activities in fabrication shop, it was

important that standardisation of different VA and NVA activities be done. i.e. activities involved in theshop must be categorized in the following three criteria-

1) Value-Adding Activity

2) Non-Value Adding Necessary Activity

3) Non-Value Adding Removable Activity

For a week, I gathered information about various activities carried out at Fabrication shop in

PES, Plant-19. Then by analyzing their importance and contribution towards project completion, these

activities were further differentiated between Value Adding and Non-Value Adding activities.

The below chart was taken as standard for any further analysis regarding VA-NVA activities.


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TIME STUDY METHODOLOGY-

1) The observer first takes some preliminary observations of the work (a pilot study) to be studied in

order to identify suitable elements which can be clearly recognized on subsequent occasions and areconvenient for measurement.

2) Further studies are then undertaken during which the operator times (records) the duration of the

activities performed during the manufacturing process.

3) For the purpose of recording, the activities are broken up into small divisions known as elements

which are then timed using a stop watch or other timing device. One of the main reasons for studying

the activity in the form of elements, rather than the activity a whole is to exactly pinpoint the weak

link in manufacturing sequence. By altering some activities, cycle time can be reduced considerably.

4) Number of cycles that should be observed depends on the nature of the work and also on the level of

accuracy of observations desired. The accuracy of readings will improve with successive

observations. There is no empirical formula to determine the number of observations to be taken for

getting accurate results.

VIDEO ANALYSIS METHODOLOGY-

1) All important activities defined in the micro process plan were recorded by video shooting them.

2) All the videos were then viewed in a production meeting held by PES Manufacturing divisional

heads and respective supervisors.

3) Any changes required in operational procedure were discussed and standardized. The same

modifications in operating procedure are then conveyed to respective workers and implemented

with immediate effect.

STOPWATCH MONITORING METHODOLOGY-

1) As activities related to fabrication are usually ongoing for hours, it was impractical to evaluate

each and every second's work. Hence, time study was done in minutes and its details are shown

on page 46.

2) Actual recorded time was then compared with theoretical time in micro process plan and

bottleneck activities are identified and efforts are taken to decrease their cycle time.


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JOB-SPECIFIC VA-NVA ANALYSIS BY TIME STUDY-

In Fabrication shop of PES, Plant 19, projects are divided among workstations and job is moved

from one workstation to another as it progresses.Supporting Structure is one of the four key components of ReGen PowerTech project, the other

three being Rotor, Brake Disc and Reinforcing Cap. The windmill project was completed within my

tenure at Godrej & Boyce Mfg. Co. Ltd. Supporting Structure occupies SS1, SS2, Plummer Block, SS3,

SS4. While Supporting Structure was in Fabrication shop, detailed VA-NVA analysis was done.

SS job ready for machining

Completed SS ready for dispatch


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EXPECTED VS. ACTUAL CYCLE TIME-

Process planning department is responsible for providing job cards stating detailed sequence of

operations to be carried out in order to complete a project. The project manager is then supposed to chalkout a micro process plan with expected cycle time and manpower requirement which may need certain

revisions as the project progresses.


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IMPORTANT IMPROVEMENTS SUGGESTED AFTER SS PRODUCTIVITY

ANALYSIS-

1) While preheating long seams, workmen should provide a metal lid long enough to cover the

whole WEP region so that maximum efficiency of preheating can be achieved.

#2 long seam welding

2) Magnetic rotary table should be provided for quicker pan/fin setup & welding.

3) Tolerance on #2 & #4 parts should be reduced in order to eliminate or reduce grinding that needs

to be done while setup.

#4 setup

4) Two teams could be deployed for fin and pan setup and tack-welding so that total cycle time for

the activity can be reduced considerably.

5) Dimension of gussets needs to be controlled more precisely. Heavy grinding effort is required for

each gusset setup. Several tryouts may be required in some cases.

6) Welding automation is the key to productivity. BhaGo automated FCAW welding technique

should be deployed as much as possible with long seams of supporting structure. Currently,

hardly any welding automation is used for supporting structure.


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7) Workers have difficulty while positioning all eight spacers correctly. This is caused by

deterioration of top and bottom surfaces of the spacers.

Supporting Structure main fixture design drawing

8) Pan locking fixture design needs to be revised to reduce the amount of efforts required for

carrying out setup of each pan. This can be done by reducing the number of bolts that must be

screwed simultaneously in order to get the pan in correct position for tacking. Currently, there

are nine bolts which must be screwed one by one which is very time consuming and laborious

process.

Pan Locking Fixture


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LOSS ANALYSYS-

SIXTEEN MAJOR LOSSES-

(1) Seven major losses that impede equipment efficiency-i. Failure losses-

Loss due to breakdown of machines is categorized under failure losses. Detailed

breakdown analysis of all machines will suffice the purpose of analyzing failure losses.

Machine breakdown time is found out using the TPM records. Losses data filled by

the operator at the end of shift is collected daily and at the end of month, collective

breakdown data is calculated and analyzed.

ii. Setup/adjustment losses-When any welding machine is set up at the start of shift, setup activities like earthing

clamping and cleaning are to be done. Any intermediate stops during welding for

current/voltage adjustments are also categorized under setup/adjustment losses.In case of semi-automatic FCAW welding, BhaGo machine is used extensively in

Fabrication shop. Setup & adjustment time for BhaGo machine is the highest among all

welding machines.

iii. Tool change losses-Time required for changing the tool of any particular machine is considered as tool

change loss. Changing wire spool of FCAW welding machine or replacing grinding wheel

of grinding machine are categorized under tool change losses.

iv. Start-up losses-Time required for getting back to work after scheduled suspension, lunch break or

shift change is said to be start-up loss. Generally, start-up losses do not affect theproductivity to such an extent that they can be considered as hindrance. Daily pep talks and

filling up of CLIT checklist usually constitute of start-up losses.

v. Minor stoppage/idling losses-Loss occurring due to minor breakdown of a machine or temporary functional

stoppage is also important.

vi. Speed losses-The difference between the design speed of a machine and actual operating speed

directly affects the cycle time of a process, accounting for speed loss. Similarly, we can

also apply this concept to fabrication processes where micro process plan is made by

experienced shop supervisor and the actual processes take longer than the estimated time inprocess plan.


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vii.Defect/rework losses-It is the most important loss occurring in fabrication department, which must be

avoided as far as possible. Defect and rework are NVA-Removable acts and material and

labor cost is added to process expenses.

LPT Defect Data

(2) Losses that can impede equipment operating rate-i. Shutdown losses-

Production time lost due to machine being shut down for some reason is categorized

under shutdown losses. Improper implementation of time reduction study, critical path and

logical cycle-setting are main reasons for shutdown losses.

(3) Five major losses that can impede human work efficiency-i. Management losses-Loss occurring due to improper management or resources, manpower, proceedings

waiting for raw materials, workmen waiting for instructions and rework are categorized

under management losses.

Management losses must be avoided at all costs. To ensure this, loss data for major

projects is maintained independently and presented to the Manufacturing Head during

project review meetings.

ii. Motion losses-Unnecessary movement of resources and materials, improper implementation of line

flow are said to be motion losses.


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iii. Line organisation losses-Losses occurring due to improper manpower planning and management on line are

said to be line organisation losses.

iv. Losses resulting from failure to automate-These are losses due to non-implementation of automated systems like auto-CO2

welding although they could be implemented to reduce cycle time and improve overall

process efficiency.

v. Measuring and adjustment losses-Man-hours lost due to inspection and measurement activities by QA personnel are

counted under measurement & adjustment losses. This loss accounts for quality defects

and rework.

(4) Three major losses that can impede effective use of production resourcesi. Yield losses-

Losses occurring due to wastage of raw material are said to be yield losses.

ii. Energy losses-Inefficient management of energy resources like electricity, compressed air, PNG and

water lead to energy losses. These losses should be minimized in order to improve overall

process efficiency.

iii. Die, jig, and tool losses-Expenses required for upkeep and maintenance of dies, jigs and other tools are also

considered as losses. Preventive maintenance and careful use should minimize this loss.


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JOB SPECIFIC LOSS ANALYSIS-

After completion of ReGen order, fabrication shop had workload of only two major projects-

Bridge & Carriage and Calandria. Detailed Losses analysis was done for the period to know more aboutwhat are the causes of any losses or delays hampering the jobs progress.


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TEST TO DETERMINE WELD DEPOSITION OF E308L ELECTRODES-

There was no established benchmark for weld deposition of E308 electrodes (SS to SS). Only

available benchmark was for CS material (E-7018)

Hence, a detailed test was conducted to set a standard for all future analysis of weld deposition

for SS to SS weld joints.

TEST PROCEDURE-

1) Three E308L electrodes of diameters 3.15mm, 4mm and 5mm respectively were also weighed in the same way.

End-to-end length was also measured using a tape.

2) An experienced welder was asked to burn the rods one by one on three different plates. Current setting was

noted from the SMAW machines display and arcing time was measured accurately using a stopwatch.

3) After completing each run, slag was removed using chipping hammer and plates were cleaned by wire brushing

& again weighed using an accurate digital scale.

4) Length and weight of all three stubs were also noted.

5) Weight of weld material deposited and weight of electrode consumed were calculated from the readings.


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WELDER EFFICIENCY & PRODUCTIVITY IN CALANDRIA STAGE I NOZZLE

WELDING-

WELDER EFFICIENCY-

With the detailed analysis of Calandria stage I welding, we can estimate the welder efficiency in

terms of the percentage of actual weld deposition over theoretical weld deposition.

It is not desirable to have any positive deviation from the theoretical weld deposition for any

nozzle as all welding-related factors are already considered by the weld estimator. It is essential to make

sure that minimum required weld deposition is always assured.

Prerequisites for calculating weld deposition-

No. of electrodes consumed & their diameters

Standard deposition of electrodes of different diameters

Diameter of

electrode

(mm)

Weight

deposition

(gm)

3.15 20

4 30

5 50

WELDER PRODUCTIVITY-

Similarly, we can also estimate the productivity by analyzing the actual time required for nozzle

welding. Its percentage over theoretical time required gives us an estimate of productivity of welders.

Any negative deviation is appreciated as it means that welding of a particular nozzle was welded

before its expected completion.

COMPARING PARAMETERS (weld deposition & welding time)-

Actual in terms of % theoretical = Actual value

Theoretical value


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PARAMETER MONITORING-

1) Quality control and traceability are two most important aims of implementing such productivity

measurement norm with Calandria stage I nozzle welding.2) When welding of a particular nozzle is completed, final weld LPT of inner and outer side of shell

is taken to check if there are any repairs in the weld. Most probably causes of repairs revealed in

LPT include slag, lack of fusion, undercut and pinholes. Corrective action has to be taken to

rectify the defect and it is considered as rework loss which accounts for wastage of both

manpower and time.

3) In order to trace the source of defect, grinding is done and the spot is then filled up and re-

offered for LPT. Ultrasonic Testing (UT) of SS material is not possible; hence it is not an option.

4) The ultimate test for completed weld joint is Radiography Testing (RT); in which the weld joint

is exposed to a radioactive source such as Iridium or Cobalt isotope. The projection is then

captured on a film which is examined to find out minute defects which cannot be detected in

other tests.

5) If any defect indications are found, subsequent repair-welding is done followed by re-RT.

6) Repair welding and subsequent grinding is extremely expensive in terms of time and material

costs; which is why welding parameters are monitored carefully.

7) After knowing the depth of defect, we can come to know which welder was responsible for that

particular pass/layer from the depth chart of the respective nozzle.

8) Comparing actual weld deposition with the deposition expected as per the weld estimator is

another major reason behind maintaining the records. If the actual deposition is higher than the

expected deposition, it can be concluded that welders are not using their electrodes properly and

training is required to educate them.


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ACTUAL CALANDRIA STAGE I NOZZLE WELDING OBSERVATIONS-


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THEORETICAL VS. ACTUAL PARAMETERS COMPARISON-

Criteria Theoretical Actual

Total Weld Deposition (kg) 119.14 120.95

Total Welding Time (hours) 259 296.75


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ANALYSIS OF CONSISTENCY TREND IN WELDER PRODUCTIVITY-

During welder productivity monitoring, consistency in just as important as productivity itself is.

It represents the ability of a welder to repeat his performance. The welder who is capable of

producing quality output with high productivity consistently is considered as the most valuable

resource.

A highly productive welder may not always be consistent. For example, consider 3 kg as the

benchmark deposition level for a shift for SMAW welding. Now, if a worker deposits nearly 7 kg

in an eight hours shift for two days and does below-par work for rest of the week, his overall

productivity for the week would still be par. But, he wouldn't be as consistent as required, which

is equally important.

A productivity consistency analysis was done on the same lines for Calandria Stage Inozzle welding.

Benchmark weld deposition for SMAW welding in Fabrication shop is 2.7 kg/shift. (as per IMS

manual, Fabrication-19)


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From the analysis, it was found that Anand was the most consistent and productive welder of all

and Nandesh was the poorest performer. The outcome was such even though Nandesh's total weld

deposition was the highest of all, and nearly twice that of Anand.


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ASSIGNMENT 1

DESIGN & IMPLEMENTATION OF WATER COOLING

ARRANGEMENT FOR CALANDRIA STAGE I NOZZLESOut of total 122 nozzles, a total of 22 radial were to be welded during stage I. Nozzles of four

different sizes were to be welded. Hence, cooling arrangements were supposed to be different for all four

sizes.

Basically, external and internal water cooling systems were to be designed separately for each

nozzle.

NEED OF WATER COOLING-

As RM for Calandria Main Shell is stainless steel, it is necessary to maintain the heat input

during welding below 2.0 kJ/mm. It is important to maintain the interpass temperature of 240

C.

Laser Gun being used to measure weld joint temperature after completing a pass

Air cooling will not suffice the purpose of maintaining the required temperature, as the amount

of heat generated during welding is much more than what can be air cooled. Water cooling provides

better rate of cooling which is essential in case of Calandria main shell.


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PRIMARY DESIGN IDEA-

For external cooling, a hollow tube of about 16 mm diameter is taken and then bent to circular

shape by hammering. Small holes of 2-3mm diameters are drilled by pneumatic drilling machine at about100mm pitch. It was reduced to 50mm to effect better cooling.

Visualisation of external water cooling system

An internal cooling system was also designed which consisted of a wooden plug with Morse

taper of about 2. After conducting trials of external cooling using circular tube with holes on its

periphery, it was observed that the temperature of welding zone was well below the interpass

temperature. Hence, it was decided that internal cooling was not required, although it would have

certainly helped in further reducing the temperature of the nozzle side of the weld region. The thickness

of shell was more than that of nozzles, which resulted in lesser heat input in the nozzle region, which

supported the shelving of internal cooling system implementation.

Recirculation of water was the most important part of the system, which meant that de-

mineralized (DM) water would need to be stored in a tank only once a day. DM water would be changed

daily in order to maintain the cleanliness of the tank and the job.


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COMPONENTS REQUIRED FOR EXTERNAL COOLING SYSTEM-

DM WATER-

De-mineralized water is used in water cooling system to prevent any corrosion andcontamination issues that may arise when water comes in contact with the shell.

DM Water Storage Tank

WATER TANK-

A medium-size water tub was identified and used a tank for storing the DM water.

Water Tank


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WATER PIPE-

A flexible pipe of sufficient diameter was used to carry the water pumped by the motor from the

water tank to the circular tube.

Water Pipe

MOTOR (1/8 hp capacity)-

An electric motor of 1/8 hp capacity was deployed for the purpose of pumping water from the

water tank to the lower surface of nozzle through the water pipe and tube arrangement.

1/8 hp motor


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T OR L JOINT-

A joint was used to route the water coming from the water tank through the pipe and circulate it

through circular tube.

T Joint L Joint

CIRCULAR RING-

A circular ring of M.S. with holes drilled on its periphery was used to shower water on the shell

and nozzle OD surface with enough pressure.

(a) (b) (c)

(a) Two separate rings

(b) Close-up of rings showing holes drilled on the top side at about 30mm pitch

(c) Two rings joined with a T-joint and a hollow rubber tube


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CLITS-

Small SS clits were used to hold the circular tube in proper position with respect to the shell O.D.

by tack welding.

Clit used to hold the circular ring in position

HOLDING AREA-

The holding area was made of four SS sheets, used as walls, attached to the base by using tack

welding (TIG) and Epoxy sealant like M-sealant. The SS sheets were inclined before being tack welded

in order to capture more water falling down from the shell.

Holding Area

WATER RECOVERY SYSTEM-

A small SS plate was bent in a way to act as an open pipe, facilitating the recovery of warm

water falling down from the weld zone, after cooling it. The recovery system was designed to send the

water from the holding area back to the water tank for recirculation. The open-pipe arrangement was

used particularly when the capacity of holding area was less to facilitate speedy water recovery.

As an option to SS plate, a water pipe was also used sometimes to send spent water back to the

water tank.


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IMPROVEMENTS IN THE WATER COOLING SYSTEM-

6) COMMON BASE PLATE-After analyzing loss data for Calandria, it was observed that high setup loss was taking its toll on

the workstation productivity. After pondering on the issue, it was decided that a common base plate

would be used as a base for I-series nozzle welding.

INITIAL SCENARIO-

Holding area for each nozzle was separate. Even if two or more separate nozzles in the same line

were to be welded, as many number of water holding arrangements were made. Setup & tack

welding of SS plates to the base was a very time consuming activity and further water proofing the

whole arrangement needed a lot of time as it could not be used before the curing time of the epoxy

sealant is passed.

IMPROVED SCENARIO-

After using common base plate and SS plates (walls) for water holding area, the setup losses

were considerably reduced as was observed by the Calandria loss data for the period of I-series

nozzle welding.

A bent SS plate was used as an open pipe for transferring spent water from the holding area to

water tank for the purpose of re-circulation.

Common Base Plate


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7) USE OF L JOINTS-INITIAL SCENARIO-

T-joints (1 input, 2 outputs) were used at the junction of water pipe and circular tube. It was

observed that the pressure of water jet was not enough when using T-joints as two water streams

separated by the T-junction would collide with each other at the opposite end on the periphery of

the circular tube, resulting in loss of overall pressure of water.

IMPROVED SCENARIO-

By using an L joint (1 input, 1 output), only single water stream would be generated and thus the

arrangement would avert the collision of water streams, as observed with T-joint. This improved the

pressure with which water comes out of the holes drilled.

The end result of the improvement was improved cooling efficiency of water and overall better

cooling rate.

IMPLEMENTATION & WORKING-

DM water is taken in water tank and PVC pipes arranged in the following manner-

1)Water Tank Motor T or L Joint

2)Water Recovery System Water Tank

Water is pumped to the circular ring with pressure enough to spray water on the OD side of the

weld joint.

After taking away heat from the weld joint, warm water falls in the water recollection area which

then flows back to the water tank to complete the cycle.

Warm water falling from the weld joint surface is cooled in the recollection system as the area is

open to air and its cooling is accelerated when it flows down from the water recollection area to

the water tank through a PVC pipe.

Design & Implementation of Productivity Measurement System in Fabrication Department

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