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Page 1 Higher Institute for Plastics Fabrication WORKBOOK for Blown Film Extrusion Practical Course Prepared by Blown Film Extrusion Department 1 st Edition 2009

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  • Page 1

    Higher Institute for Plastics Fabrication

    WORKBOOK

    for

    Blown Film Extrusion

    Practical Course

    Prepared by

    Blown Film Extrusion Department

    1st Edition 2009

  • Page 2

    Workbook for Blown F i lm Pract ica l Course

    ACKNOWLEDGEMENT

    In its program to continuously improve the quality of instructions at the

    Higher Institute for Plastics Fabrication, the Curriculum Steering Committee

    initiated the creation of the workbooks for all practical courses being offered

    in the Institute. The Committee is headed by Dr. Khaled Al-Ghefaili, and the

    members are Dr. Ahmad Al-Ghamdi, Mr. Hiroshi Takeshita, Engr. Issa Al-

    Khormi, Mr. Sumio Iwase, Mr. Kazuhiko Sawada, Mr. Sanjay Rawat, Mr.

    Zakaria Musa, and Mr. Virgilio Calpe.

    This is the HIPF Workbook for Injection Molding for Practical Course. The

    contents of this workbook were compiled through the efforts of the members

    of the Blown Film Department, namely, Raul R. Clave (Head of the

    Department), Isagani Aldover, Philip Floyd Yumul, Jovanny Quilala, Jovef

    Pangue, Alfred Bacosa, Kirankumar Daraji (Senior Instructors) and Mr.

    Sumio Iwase and Mr. Takuma Nakashima (Blown Film Expert Advisers).

    Editing, formatting and design by Virgilio Calpe.

    February 2009

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    Workbook for Blown F i lm Pract ica l Course

    TABLE OF CONTENTS

    Introduction . 4

    Course Objectives . 5

    General Safety Guidelines ... 6

    Grades Summary Sheet ... 7

    Workshop Activities

    Activity 1Basic Theory of Blown Film Extrusion .. 8

    Activity 2Polyethylene Films 14

    Activity 3Emergency Stop and Safety Devices . 19

    Activity 4Blown Film Die 26

    Activity 5Blown Film Air Cooling Ring .. 31

    Activity 6Blown Film Width and Thickness .. 37

    Activity 7Corona Treatment . 42

    Activity 8Flexographic Printing 48

    Activity 9Bag Making . 55

    Activity 10Polyethylene Film Recycling . 64

    Glossary . 92

    References ... 110

    Activity 11Practice Plant Operations (LDPE) . .. 73

    Activity 12Practice Plant Operations (LLDPE) . . 81

    Formulas 89

    Activity 13Practice Plant Operations (HDPE) . .. 85

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    Workbook for Blown F i lm Pract ica l Course

    INTRODUCTION

    Blown film extrusion is one of the most commonly used thin-gauge

    fabrication processes in the world. The majority of the commodity films

    such as grocery bags, agricultural films and other flexible packaging films

    used by consumers are produced by this method. The process of producing

    film by extruding molten resin into a continuous tube is simple. Yet, in fact

    the system is one of the most complex and sensitive of all the plastics

    fabricating technologies and it presents many inherent difficulties.

    A simple blown film line consists of an extruder, die, air ring, iris or bubble

    cage, collapsing frame, and a winder.

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    Workbook for Blown F i lm Pract ica l Course

    COURSE OBJECTIVES

    The purpose of this workbook is to enable the trainees to understand and

    carry out important activities being done in a blown film extrusion process.

    Focus will be on the most important functions of the machine and the

    terminologies used in the enterprise.

    Upon successful completion of this course, the trainee will be able to:

    Know the main components of film extruders and their purposes.

    Describe blown film extrusion process.

    Identify common polyethylene films.

    Perform emergency stop using emergency switches.

    Know the operation of an air ring, die, nip rolls and gusseting equipment.

    Know the operation of a simple flexographic in-line printer.

    Know the basic operation of a recycling machine.

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    Workbook for Blown F i lm Pract ica l Course

    GENERAL SAFETY PRECAUTIONS

    Instead of starting operations carelessly, all trainees should discuss the

    following before starting any activity:

    (1.) What types of activities are we going to do?

    (2.) What kind of risks are hidden behind those types of activities?

    (3.) What should we do to avoid those risks?

    Here are some safety reminders to always keep in mind:

    Keep the work area clean at all times.

    Use proper hand gloves. Avoid using loose hand gloves.

    Use the appropriate tool and wear protective dry gloves when you throw

    away purged resin.

    Do not lean against the cage guard of the ladder when you work.

    Pay attention to where your hands are to ensure that your hands are not

    pinched between rollers and other rotating equipment.

    Do not run the machine without the protective covers on rotating parts.

    Avoid clothing or accessories that could easily be pinched or caught in

    machines.

    Specifically, do not wear items that hang far from your neck such as long

    necklaces and IDs. Do not wear rings or loose bracelets. Do not wear

    clothing that is pleated, sags or has strings. Make sure that you button or

    fasten your shirt and jacket cuffs, pant cuffs and jacket hem.

    Do not stand in front of the die.

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    Workbook for Blown F i lm Pract ica l Course

    GRADES SUMMARY SHEET

    Trainee Name: _________________________ Group: ________

    Semester ___ School Year ___________

    ACTIVITIES GRADE

    Activity 1Basic Theory of Blown Film Extrusion

    Activity 2Polyethylene Films

    Activity 3Emergency Stop and Safety Devices

    Activity 4Blown Film Die

    Activity 5Blown Film Air Cooling Ring

    Activity 6Blown Film Width and Thickness

    Activity 7Corona Treatment

    Activity 8Flexographic Printing

    Activity 9Bag Making

    Activity 10Polyethylene Film Recycling

    Activity 11Practice Plant Operations (LDPE)

    Activity 12Practice Plant Operations (LLDPE)

    Activity 13Practice Plant Operations (HDPE)

    AVERAGE GRADE

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    Workbook for Blown F i lm Pract ica l Course

    THEORETICAL BACKGROUND

    Blown films are created by feeding plastics pellets into an extruder where

    they are melted and homogenised before they are pumped through a circular

    blown film die. The melted plastics form a continuous tube which is drawn

    from the die. It is inflated and simultaneously cooled by rapidly moving air.

    The tube, also called a bubble, is then flattened as it passes the collapsing

    frames and drawn through nip rolls and over idler rolls to a winder which

    pulls and winds the finished rolls of film.

    A typical film blown film machine consists of the following five major units:

    Extruder unitconverts the solid pellets into hot melt.

    Die unitforms the hot melt into tube.

    Cooling unitcools down and solidifies the hot melt.

    Take-off unitpulls and flattens the tube at constant speed.

    Winding unitwinds-up the flattened tube into finish rolls.

    WORKSHOP ACTIVITY #1

    Basic Theory of Blown Film Extrusion

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    Workbook for Blown F i lm Pract ica l Course

    OBJECTIVES OF THE ACTIVITY

    1. To learn the basics of operating a blown film machine

    2. To identify the parts of the five major units of a blown film and their

    elements

    PROCEDURE

    PART IThe Basic Operations of Blown Film Machine

    1. Go to the Workshop floor and observe any of the blown film machine

    that is being run by your Instructor.

    2. Using data sheet on the following pages, list down accordingly the steps

    of the blown film process you have observed.

    Example:

    Step 1. Put material in the hopper.

    Step 2. etc

    PART IIThe Five Major Units of a Blown Film Machine

    1. Using the drawing of Blown Film Machine in your data sheet, label the

    following:

    a. name of the part/s of each major units.

    b. name the other elements needed in the process.

    WORKSHOP ACTIVITY #1Basic Theory of Blown Film Extrusion

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    DATA SHEET

    PART IThe Basic Operations of Blown Film Machine

    Steps in Blown Film Operations

    ACTIVITY #1Basic Theory of Blown Film Extrusion

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 1 of 4 Page 1 of 4 Page 1 of 4 Page 1 of 4

    Description of the Step Step No.

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    DATA SHEET

    PART IIThe Five Major Units of a Blown Film Machine

    ACTIVITY #1Basic Theory of Blown Film Extrusion

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 2 of 4 Page 2 of 4 Page 2 of 4 Page 2 of 4

    Properly label the Blown Film

    Proce

    ss Diagram

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    Workbook for Blown F i lm Pract ica l Course

    QUESTIONS & EXERCISES

    A. Choose the correct answer.

    1. What is the most common material used for blown films?

    (a.) PVC (c.) Nylon

    (b.) PET (d.) PE

    2. What is the common type of blown film used all over the world?

    (a.) Downward BF (c.) Upward BF

    (b.) Horizontal BF (d.) None of the above

    3. What part of the blown film machine makes the screw rotates?

    (a.) blower (c.) haul-off

    (b.) main motor (d.) winder

    4. What is the process of feeding a single die with two or more different

    polymer melt streams?

    (a.) blower (c.) haul-off

    (b.) main motor (d.) none of the above

    B. How does blown film differs from other plastics fabrications?

    Check () if applicable, and cross out () if not applicable.

    WORKSHOP ACTIVITY #1Basic Theory of Blown Film Extrusion

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 3 of 4 Page 3 of 4 Page 3 of 4 Page 3 of 4

    PROCESS Die Mould Screw and

    Barrel

    Haul-off /

    Take-off Winder

    Blown Film

    Extrusion

    Blow

    Molding

    Pipe

    Extrusion

    Injection

    Molding

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    Workbook for Blown F i lm Pract ica l Course

    CONCLUSION & RECOMMENDATIONS

    INSTRUCTORS COMMENTS

    WORKSHOP ACTIVITY #1Basic Theory of Blown Film Extrusion

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    TRAINEES GRADE

    FOR THIS ACTIVITY

    ________________________

    INSTRUCTORS SIGNATURE

    Cut R

    eport F

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    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 4 of 4 Page 4 of 4 Page 4 of 4 Page 4 of 4

    DATE: __________________

    DATE: __________________

    ________________________

    TRAINEES SIGNATURE

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    Workbook for Blown F i lm Pract ica l Course

    THEORETICAL BACKGROUND

    The ethylene polymer is available in three main grades, low, medium and

    high density film.

    Polyethylene, PE, film is slightly opaque, the opacity increasing with

    density.

    PE film is waxy to the touch, and is a good moisture barrier.

    Low and medium density PE films are flexible even when cold.

    PE is readily heat sealed.

    High density PE film is suitable for boil-in-the-bag packs, whereas low

    and medium density films are not.

    PE film that has a lower MFR means a higher molecular weight and

    better mechanical strength.

    WORKSHOP ACTIVITY #2

    Polyethylene Films

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    Workbook for Blown F i lm Pract ica l Course

    OBJECTIVES OF THE ACTIVITY

    1. To learn the physical properties of Polyethylene (PE) films

    2. To compare the differences among the three common types of PE films

    used in blown film packaging

    PROCEDURE

    PART IPhysical Characteristics of PE Films

    1. Collect three samples for each type of the PE films from the plant

    LDPE @ 400mm & 30microns

    LLDPE @ 400mm & 30microns

    HDPE @ 400mm & 30microns

    2. Correctly label the different films.

    3. Each film sample should have the same thickness, length and width.

    4. Try to stretch each film and write your observation in your data sheet.

    PART IIProcess Parameters for PE Films

    1. Try to find the Melt Temperature and Pressure for processing each type

    of PE films.

    2. Write your data in the table provided in your data sheet.

    3. Compare MFR, Density, Melt Temperature, and Pressure for each type of

    PE films.

    4. Which materials do you think is the easiest to process?

    WORKSHOP ACTIVITY #2Polyethylene Films

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    DATA SHEET

    PART IPhysical Characteristics of PE Films

    Stretch the plastics samples:

    PART IIProcess Parameters for PE Films

    ACTIVITY #2Polyethylene Films

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 1 of 3 Page 1 of 3 Page 1 of 3 Page 1 of 3

    PE Sample

    MFR Density Extruder Melt Temperature

    Extruder Melt Pressure

    LDPE 0.2 to 5 0.912 to 0.925

    LLDPE 0.5 to 2 0.912 to 0.925

    HDPE 0.03 to 0.1 0.945 to 0.955

    PE Sample Observations

    LDPE

    (400mm, 30microns)

    LLDPE

    (400mm, 30microns)

    HDPE

    (400mm, 30microns)

    Based on the above data, which materials is easy to process?

    Why?

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    Workbook for Blown F i lm Pract ica l Course

    QUESTIONS & EXERCISES

    Choose the correct answer and mark ( ) the correct ones.

    1. Which of these films has a better clarity?

    a. LDPE

    b. LLDPE

    c. HDPE

    2. Which is the toughest among these polyethylene films?

    a. HDPE

    b. LDPE

    c. LLDPE

    3. Which blown film bag is suitable for carrying more weight?

    a. LLDPE

    b. LDPE

    c. HDPE

    4. Choose the correct application of LDPE film.

    a. food packaging

    b. shopping bag

    c. garments packaging

    d. floor covering

    5. Which of these films can be stretch more?

    a. HDPE

    b. LDPE

    c. LLDPE

    WORKSHOP ACTIVITY #2Polyethylene Films

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 2 of 3 Page 2 of 3 Page 2 of 3 Page 2 of 3

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    Workbook for Blown F i lm Pract ica l Course

    WORKSHOP ACTIVITY #2Polyethylene Films

    CONCLUSION & RECOMMENDATIONS

    INSTRUCTORS COMMENTS

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    TRAINEES GRADE

    FOR THIS ACTIVITY

    ________________________

    INSTRUCTORS SIGNATURE

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 3 of 3 Page 3 of 3 Page 3 of 3 Page 3 of 3

    DATE: __________________

    DATE: __________________

    ________________________

    TRAINEES SIGNATURE

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    Workbook for Blown F i lm Pract ica l Course

    THEORETICAL BACKGROUND

    MACHINE SAFETY GUARDS & DEVICES

    Safety devices in facilities, machinery and equipment are an essential means

    of ensuring worker safety. Foolproof devices, failsafe devices and others are

    used to ensure intrinsic (essential) safety. These devices are usually built

    into facilities, machinery and equipment so that workers cannot easily

    remove them.

    The foolproof function is a safety mechanism designed with a focus on

    human factors. On the other hand, the failsafe function is a safety

    mechanism designed with a focus on the protection of facilities, machinery

    and equipment.

    Types of safety devices typically used in blown film machine:

    Mechanical Interlock

    Electrical Interlock

    All Dangerous spots of the blown film line must be secured by suitable

    protective devices. If proper guards cannot be mounted due to the conditions

    at hand, these areas are secured by Emergency devices.

    Guarding and Barriers

    The purpose of machine guarding and barrier is to protect the machine

    operator and other employees in the work area from hazards created by

    moving parts, rotating parts, flying chips & sparks. Some examples of this

    are barrier guards, safety gates, etc.

    WORKSHOP ACTIVITY #3

    Emergency Stop and Safety Devices

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    Workbook for Blown F i lm Pract ica l Course

    THEORETICAL BACKGROUND continued

    WORKSHOP ACTIVITY #3Emergency Stop and Safety Devices

    Pull-Down

    Electrical Interlock

    Safety Interlock Switch

    Push

    WARNING SIGN WARNING SIGN

    SAFETY COVER GUARD RAILS

    EMERGENCY STOP EMERGENCY STOP

    SAFETY SWITCH SAFETY GATE

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    Workbook for Blown F i lm Pract ica l Course

    OBJECTIVES OF THE ACTIVITY

    1. To know the purposes of each of the safety devices installed in a blown

    film machine

    2. To learn how to pause or stop the blown film machine in emergency

    cases

    3. To develop awareness of the dangers of blown film machine if safety

    devices are tampered or by-passed

    PROCEDURE

    Types of Safety Devices Typically Used in Blown Film Machines

    Walk around the blown film machine assigned to you by your Instructor and

    try to locate all the safety devices and the emergency stop buttons.

    PART ISafety Devices and their Functions

    1. In your data sheet, write down the names of the safety devices and their

    functions and answer the questions.

    PART IIEmergency Stops

    1. In your data sheet, indicate all the emergency stop buttons of the blown

    film machine available in WS02 and answer all the questions.

    WORKSHOP ACTIVITY #3Emergency Stop and Safety Devices

  • Page 22

    DATA SHEET

    PART ISafety Devices and their Functions

    Safety Devices of Blown Film Machine, where are they?

    ACTIVITY #3Emergency Stop and Safety Devices

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 1 of 4 Page 1 of 4 Page 1 of 4 Page 1 of 4

    SAFETY DEVICES of BLOWN FILM MACHINE

    1.

    2.

    3.

    4.

    5.

    1. Do these safety devices really help by reminding you of the danger if

    they are not activated?

    2. How?

    YESYESYESYES NONONONO

  • Page 23

    DATA SHEET

    PART IIEmergency Stops

    Emergency stop buttons of Blown Film Machine, where are they?

    ACTIVITY #3Emergency Stop and Safety Devices

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 2 of 4 Page 2 of 4 Page 2 of 4 Page 2 of 4

    1. When are we going to use the emergency stop buttons, is it during

    scheduled shutdown?

    2. Why?

    3. If something happens to the machine or to the operator and we need to

    stop immediately, are we going to use the emergency stop?

    4. Why?

    YESYESYESYES NONONONO

    YESYESYESYES NONONONO

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    Workbook for Blown F i lm Pract ica l Course

    QUESTIONS & EXERCISES

    Choose the correct answer.

    1. What type of emergency device is installed above and across the

    width of the winding station?

    (a.) emergency stop button (c.) emergency stop cord

    (b.) warning alarm (d.) none of the above

    2. What warning sign is available in the machine indicating danger of

    being burn?

    3. What will you do to stop the machine in case of emergency?

    (a.) switch off the main switch

    (b.) leave the machine

    (c.) press the Emergency Stop push button

    (d.) follow the shutdown procedure

    4. Which mandatory safety sign that informs operator to wear hand

    protection?

    5. Which of the following is an example of safeguarding devices?

    (a.) printing gear cover (b.) railings

    (b.) winder gates (c.) all of the above

    WORKSHOP ACTIVITY #3Emergency Stop and Safety Devices

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 3 of 4 Page 3 of 4 Page 3 of 4 Page 3 of 4

    (a.) (b.)

    (c.) (d.)

    (a.) (b.)

    (c.) (d.)

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    Workbook for Blown F i lm Pract ica l Course

    WORKSHOP ACTIVITY #3Emergency Stop and Safety Devices

    CONCLUSION & RECOMMENDATIONS

    INSTRUCTORS COMMENTS

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    TRAINEES GRADE

    FOR THIS ACTIVITY

    ________________________

    INSTRUCTORS SIGNATURE

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 4 of 4 Page 4 of 4 Page 4 of 4 Page 4 of 4

    DATE: __________________

    DATE: __________________

    ________________________

    TRAINEES SIGNATURE

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    THEORETICAL BACKGROUND

    In various kinds of plastics fabrication processes, molten resin that leaves the

    extruder is forced through an orifice (opening, slit) called a die. By this die

    the molten resin is given its final shape appropriate for the end product.

    A die used for blown film extrusion has an annular (ring-shaped) outlet

    (called a lip) through which the molten resin passes. Such a die is called a

    circular die. The size of a die is expressed by the lip diameter. The lip

    diameter ranges from a small diameter of about 30 mm to a large diameter of

    about 1,500 mm.

    The Two Types of Die Lip Gap Adjustments: Figure 4.1

    WORKSHOP ACTIVITY #4

    Blown Film Die

    Upper Die Goes that way

    Tightening the bolt

    Upper Die

    Tightening the bolt

    Upper Die Goes that way

    Upper Die

    A

    B

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    Workbook for Blown F i lm Pract ica l Course

    OBJECTIVES OF THE ACTIVITY

    1. To learn the basic principles of die mechanisms

    2. To understand the die mechanisms and how to adjust the lip gap

    PROCEDURE

    PART IDie Lip Adjustment

    1. Prepare the half die head available in the Workshop.

    2. Examine carefully what type of die lip gap adjustment the die has.

    3. Confirm the movement of the die lip. Confirm whether it is A- or B-type

    lip gap adjustment.

    4. When making adjustment, loosen the bolt on the other side first. Refer to

    Figure 4.1:

    For A type, tightening the bolt will widen the gap.

    For this type, when the die ring is screwed in, the ring is moved in a

    way that pulls the ring with the bolt to widen the lip gap (see Figure

    4.1).

    For B type, tightening the bolt will narrow the gap.

    For this other type, when the die ring is screwed in, the ring is moved

    in a way that pushes the ring with the bolt to narrow the lip gap (see

    Figure 4.1).

    5. Try turning the bolts of your die and observe the outer lip movement of

    the die. Answer all the questions in your data sheet.

    PART IIParts of the Die

    1. Properly label the parts of the die using the drawing found in your data

    sheet.

    WORKSHOP ACTIVITY #4Blown Film Die

    Important!

    Before you adjust the gap, you should know which type of adjust-you should know which type of adjust-you should know which type of adjust-you should know which type of adjust-able die ring is used for the die able die ring is used for the die able die ring is used for the die able die ring is used for the die available. You should also under-stand that the adjustable die ring just moves horizontally as a as a as a as a

    whole whole whole whole by rotating the adjusting bolt.

  • Page 28

    DATA SHEET

    PART IDie Lip Adjustment

    ACTIVITY #4Blown Film Die

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 1 of 3 Page 1 of 3 Page 1 of 3 Page 1 of 3

    1. Referring to the Figure 4.1, what type of die do we have in Workshop 02

    Blown Film?

    2. What happens when you tighten the bolt of this type?

    3. In your own opinion, if you widen the die lip gap, does this makes the

    corresponding blown film wall thicker?

    4. Why?

    PART IIParts of the Die

    AAAA----TypeTypeTypeType BBBB----TypeTypeTypeType

    YESYESYESYES NONONONO

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    Workbook for Blown F i lm Pract ica l Course

    QUESTIONS & EXERCISES

    1. It is the part of the Blown Film machine where the molten resin is forced

    through its round opening slit and forms a tube.

    a. screw and barrel

    b. adapter

    c. die

    d. none of these

    2. Describe briefly how the material flows as it enters the spiral and outside the

    spiral.

    _______________________________________________________________

    _______________________________________________________________

    _______________________________________________________________

    _______________________________________________________________

    4. When the die is not properly centered, why is a thinner film produced from the

    wider die gap and a thicker film from the narrower gap?

    _______________________________________________________________

    _______________________________________________________________

    _______________________________________________________________

    WORKSHOP ACTIVITY #4Blown Film Die

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 2 of 3 Page 2 of 3 Page 2 of 3 Page 2 of 3

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    WORKSHOP ACTIVITY #4Blown Film Die

    CONCLUSION & RECOMMENDATIONS

    INSTRUCTORS COMMENTS

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    TRAINEES GRADE

    FOR THIS ACTIVITY

    ________________________

    INSTRUCTORS SIGNATURE

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 3 of 3 Page 3 of 3 Page 3 of 3 Page 3 of 3

    DATE: __________________

    DATE: __________________

    ________________________

    TRAINEES SIGNATURE

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    THEORETICAL BACKGROUND

    Blown film air rings are used primarily to stabilize the bubble and

    secondarily to cool the melt. In plastics forming, a circular manifold

    distributes an even flow of cool air into a hollow tubular form passing

    through the manifold.

    An air ring is installed just above the die in an upward air cooling blown film

    machine. The air outlet called a lip (or slit) has an annular shape that

    surrounds the molten resin extruded from the die. Air is introduced into the

    ring by the blower, and the air is turned into a uniform flow inside the air

    ring. Then the air is blown through the lip against the molten resin for

    cooling. If the flow of air blown out of the lip is not uniform, it leads to non-

    uniform cooling. As a result, film thickness will be uneven. To prevent this,

    the air ring is designed to ensure uniform air flow over the entire lip.

    As the molten resin is cooled, it becomes frosty, or less clear (transparent),

    and a solidification border appears. This borderline is called a frost line.

    WORKSHOP ACTIVITY #5

    Blown Film Air Cooling Ring

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    Workbook for Blown F i lm Pract ica l Course

    WORKSHOP ACTIVITY #5Blown Film Air Cooling Ring

    PA

    RT

    S O

    F A

    SIN

    GL

    E L

    IP B

    LO

    WN

    FIL

    M A

    IR R

    ING

  • Page 33

    Workbook for Blown F i lm Pract ica l Course

    OBJECTIVES OF THE ACTIVITY

    1. To know the importance of air ring to blown film extrusion

    2. To understand the construction of an air ring and how to adjust it

    PROCEDURE

    1. Run the blown film line assigned to you by your Instructor.

    2. With the supervision of your Instructor, set the parameters to produce a

    30microns by 300mm lay flat width film.

    3. Once the process has stabilized (as checked by your Instructor), adjust

    the threaded adjusting ring of the air ring by the doing the following

    trials:

    Trial 1Turn the adjusting ring one-fourth ( ) down

    Trial 2Turn the adjusting ring another one-fourth ( ) down

    Trial 3Turn the adjusting ring still another one-fourth ( )

    down

    Trial 4Turn the adjusting ring one-fourth ( ) upward

    Trial 5Turn the adjusting ring another one-fourth ( ) upward

    4. Allow 5minutes intervals for each trial and ensure that the bubble is

    stable each time.

    5. For each trial, observe what will happen to the bubble and take note of

    what happens to the height of the frost line.

    6. Write all your observations on the table provided in your data sheet, and

    answer all the questions.

    WORKSHOP ACTIVITY #5Blown Film Air Cooling Ring

  • Page 34

    DATA SHEET

    OBSERVATIONS

    ACTIVITY #5Blown Film Air Cooling Ring

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 1 of 3 Page 1 of 3 Page 1 of 3 Page 1 of 3

    Trial

    No.

    Number of Turns

    and Direction

    Pressure

    Reading Bubble Observations

    1 turn down

    2 another turn down

    3 another turn down

    4 turn upward

    5 another turn upward

    1. When the threaded adjustable ring is adjusted downwards, what happens

    to the frost line height? goes up or down?

    2. What type of air ring does workshop 02 blown film has,

    Is it single lip or dual lip?

    3. How did you know that it is a _____________lip?

    4. If the inside of the air ring is dirty and causing obstruction, will you have

    an even flow of air in the bubble, yes or no?

    5. Does this obstruction cause uneven thickness of the film, yes or no?

    goes upgoes upgoes upgoes up goes downgoes downgoes downgoes down

    single lipsingle lipsingle lipsingle lip dual lipdual lipdual lipdual lip

    yesyesyesyes nononono

    yesyesyesyes nononono

  • Page 35

    Workbook for Blown F i lm Pract ica l Course

    QUESTIONS & EXERCISES

    1. _______________________is the part of the Blown Film machine that

    uniformly cools and then evenly solidifies (make solid) the molten resin

    extruded from the die.

    2. The blowing angle should be appropriately set depending on the type of

    resin is used, the type of product being made, and other factors.

    True or False?

    3. In the given drawing below, the air ring is called a dual lip because it has

    _______________, _________________, and ____________________.

    4. In the given drawing below, which of these two air rings is used for

    LLDPE and which is for HDPE?

    _________ is for LDPE _________ is for HDPE

    WORKSHOP ACTIVITY #5Blown Film Air Cooling Ring

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 2 of 3 Page 2 of 3 Page 2 of 3 Page 2 of 3

  • Page 36

    Workbook for Blown F i lm Pract ica l Course

    WORKSHOP ACTIVITY #5Blown Film Air Cooling Ring

    CONCLUSION & RECOMMENDATIONS

    INSTRUCTORS COMMENTS

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    TRAINEES GRADE

    FOR THIS ACTIVITY

    ________________________

    INSTRUCTORS SIGNATURE

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 3 of 3 Page 3 of 3 Page 3 of 3 Page 3 of 3

    DATE: __________________

    DATE: __________________

    ________________________

    TRAINEES SIGNATURE

  • Page 37

    Workbook for Blown F i lm Pract ica l Course

    THEORETICAL BACKGROUND

    The width (lay-flat width) and thickness of the film to be made are always

    specified in blown film extrusion. The operators need to set the width and

    thickness to the specified values correctly and maintain them within the

    target level during the processing. Once the process is started, first adjust the

    lay-flat width to the specified value. The screw rotation speed shall be set to

    the predetermined speed and the amount of air to be introduced into the

    bubble shall be adjusted. Then the film thickness shall be next step.

    In blown film extrusion, there are various kinds of operation requirements

    that directly influence on the shape of the bubble. Examples of these

    requirements are extruder take-off speed and the amount of air that enters

    the bubble. In particular, they affect the bubble size and vary the film

    thickness and lay-flat width.

    WORKSHOP ACTIVITY #6

    Blown Film Width and Thickness

    D

    Rolled Film

    W t

    tttt = thickness of film

    W= width of film

  • Page 38

    Workbook for Blown F i lm Pract ica l Course

    OBJECTIVES OF THE ACTIVITY

    1. To learn how to adjust the width and thickness of a blown film bubble

    PROCEDURE

    1. Run the blown film line assigned to you by your Instructor.

    2. With the supervision of your Instructor, set the parameters to produce a

    30microns by 300mm lay flat width film.

    3. Once the process has stabilized (as checked by your Instructor), record

    the take-off speed and winder tension on the table in your data sheet

    under Trial 0.

    4. Then do the following trials, each time observing what will happen to the

    film thickness and film width. Record the new thickness and width on

    the table in your data sheet.

    5. Answer all questions relating to each trial.

    WORKSHOP ACTIVITY #6Blown Film Width and Thickness

    TRIAL No. ACTION

    Trial No.1 Increase the take-off speed by 2m/min. Slightly add

    tension on winder to adjust the film tension.

    Trial No.2 Open the air valve and let air enter the bubble for at

    least 2 minutes. Wait for another 3minutes. Let your

    instructor stabilize the bubble. Observe what will hap-

    pen to the bubble.

    Trial No.3 Increase the take-off speed by 2m/min. Slightly add

    tension to winder to adjust the film tension. Observe

    again what will happen to the thickness of the film.

    Trial No.4 Open the air valve and let air enter the bubble for at

    least 2minutes. Wait for another 3minutes. Try to sta-

    bilize the bubble by yourself while the instructor

    guides you. Observe what will happen to the bubble.

  • Page 39

    DATA SHEET

    DATA & OBSERVATIONS

    ACTIVITY #6Blown Film Width and Thickness

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 1 of 3 Page 1 of 3 Page 1 of 3 Page 1 of 3

    Trial

    #

    Take-off Speed,

    m/min

    Film Thickness,

    m

    Winder

    Tension, N Width, mm

    0 30 microns 300mm

    1

    2

    3

    4

    1. When the haul-off speed is increased in Trial No.1, did the thickness also

    increased, yes or no?

    2. When you add some more compressed air in Trial No.2, did the width of

    the film increased, yes or no?

    3. What happened to the bubble when you increased again the haul-off

    speed in Trial No.3?

    4. What happened to the width when you add more compressed air in Trial

    No.4?

    yesyesyesyes nononono

    yesyesyesyes nononono

  • Page 40

    Workbook for Blown F i lm Pract ica l Course

    QUESTIONS & EXERCISES

    A. Choose the correct answer.

    1. What happens to the lay-flat width if more air is introduced into the

    bubble?

    (a.) no change (c.) increase

    (b.) decrease (d.) none of the above

    2. If the extruder screw speed is increased, what happens to the film

    average thickness?

    (a.) no change (c.) increase

    (b.) decrease (d.) none of the above

    3. What happens to the film average thickness if the take-off speed

    increased?

    (a.) no change (c.) increase

    (b.) decrease (d.) none of the above

    4. If the extruder screw speed is decreased, what happens to the film

    average thickness?

    (a.) no change (c.) increase

    (b.) decrease (d.) none of the above

    5. What happens to the film average thickness if the take-off speed

    decreased?

    (a.) no change (c.) increase

    (b.) decrease (d.) none of the above

    WORKSHOP ACTIVITY #6Blown Film Width and Thickness

    Cut R

    eport F

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    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 2 of 3 Page 2 of 3 Page 2 of 3 Page 2 of 3

    B. How do you decrease the width of lay flat tube?

    C. How do you increase the thickness of the film?

  • Page 41

    Workbook for Blown F i lm Pract ica l Course

    WORKSHOP ACTIVITY #6Blown Film Width and Thickness

    CONCLUSION & RECOMMENDATIONS

    INSTRUCTORS COMMENTS

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    TRAINEES GRADE

    FOR THIS ACTIVITY

    ________________________

    INSTRUCTORS SIGNATURE

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 3 of 3 Page 3 of 3 Page 3 of 3 Page 3 of 3

    DATE: __________________

    DATE: __________________

    ________________________

    TRAINEES SIGNATURE

  • Page 42

    Workbook for Blown F i lm Pract ica l Course

    THEORETICAL BACKGROUND

    If a corona discharge is generated in air, ozone (O3) is created from the

    oxygen (O2) in the air. Ozone is a powerful oxidizing gas. This ozone

    oxidizes the surface of plastics film to make it easier for the ink to stick

    to the film. This method of treating a plastics film surface is called

    corona discharge treatment.

    The corona discharge treatment equipment is made up of a high

    frequency generator, an electrode, and a treater roll.

    The wetting tension of PE film and PP film that have not been surface

    treated is around 30 to 35 mN/m. The tension appropriate for printing on

    these kinds of film is said to be normally around 40 to 45 mN/m. So,

    what is wetting tension?

    Treated film surface can be checked by measuring the wetting tension of

    the film surface. The wetting tension is an indication of the wettability of

    a solid surface.

    Normally, wetting tension of a film that is not surface treated is around

    30 to 35 mN/m compared to a treated film which has 40 to 45mN/m.

    WORKSHOP ACTIVITY #7

    Corona Treatment

  • Page 43

    Workbook for Blown F i lm Pract ica l Course

    Theoretical background continued

    This activity will explain how wettability works with the polyethylene

    film. Below is the schematic drawing of a corona discharge machine

    (corona treater).

    WETTING TENSION MEASUREMENT

    The approximate wetting tension of a film can measured by using wetting

    ink supplied by Polyrema. The ink is used to write on the surface of the

    film and the ink value where there is no run-off corresponds to the wet-

    ting tension of the film.

    WORKSHOP ACTIVITY #7Corona Treatment

  • Page 44

    Workbook for Blown F i lm Pract ica l Course

    OBJECTIVES OF THE ACTIVITY

    1. To know the importance of corona treater in blown film printing

    2. To know how corona treater affects the film quality during secondary

    processes

    PROCEDURE

    1. Run a blown film line.

    2. Produce a 30microns by 300mm lay flat width LLDPE film. Make sure

    film passes the corona discharge machine.

    3. Once the blown film is stabilized and checked by your instructor, get

    film samples without the corona treatment, and then with corona

    treatments at different corona treatment settings.

    4. Properly label each sample.

    5. Check the wettability of each sample using the wetting ink supplied by

    POLYREMA.

    6. Follow the following settings for the trials:

    7. Your Instructor will demonstrate how the wetting ink is used. Start from

    the lowest wetting ink value to the highest, and record the trial results in

    your data sheet for each of the sample.

    8. Record whether run-off occurs or not when the sample is tested with

    each wetting ink values.

    9. Answer all questions regarding your observations.

    WORKSHOP ACTIVITY #7Corona Treatment

    TRIAL NO. CORONA TREATER SETTING

    1 0% treater setting (no corona treatment)

    2 40% treater setting

    3 70% treater setting

    4 90% treater setting

  • Page 45

    DATA SHEET

    RUN-OFF OBSERVATIONS

    ACTIVITY #7Corona Treatment

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 1 of 3 Page 1 of 3 Page 1 of 3 Page 1 of 3

    Trial

    No.

    Did the line run-off?

    Wetting Ink 42 Wetting Ink 44 Wetting Ink 46

    1 0%

    2 40%

    3 70%

    4 90%

    Treater

    Setting

    yesyesyesyes nononono

    yesyesyesyes nononono

    yesyesyesyes nononono

    yesyesyesyes nononono

    yesyesyesyes nononono

    yesyesyesyes nononono

    yesyesyesyes nononono

    yesyesyesyes nononono

    yesyesyesyes nononono

    yesyesyesyes nononono

    yesyesyesyes nononono

    yesyesyesyes nononono

    1. What happened to the wetting ink applied on the first film sample? Did

    the liquid line run-off? What does this broken line shows?

    2. For the 2nd sample (Trial #2) how did the wetting ink behave in the

    film? Did it run-off too? What does this mean?

    4. For the 3rd sample (Trial #3), do you think the value of the corona dis-

    charge is very good for printing? Why?

    4. For the 4th sample (Trial #4), do you think the value of the corona dis-

    charge is very good for printing? Why?

    5. What about sealing this film from Trial #4, do you think that the seal

    will be very good?

  • Page 46

    Workbook for Blown F i lm Pract ica l Course

    QUESTIONS & EXERCISES

    1. The method of treating film surface is called

    a. gusseting

    b. sealing

    c. corona discharge treatment.

    2. What is the normal surface tension for untreated PE films?

    a. 20-30 mN/mtr

    b. 30-35 mN/mtr

    c. 40-45mN/mtr

    3. Using the wetting liquid application and marking a line on the film, if

    the line breaks-off or runs-off this means the film is

    a. untreated

    b. treated

    4. Write down the three major parts of a corona discharge machine.

    a. ______________________________

    b. ______________________________

    c. ______________________________

    WORKSHOP ACTIVITY #7Corona Treatment

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 2 of 3 Page 2 of 3 Page 2 of 3 Page 2 of 3

  • Page 47

    Workbook for Blown F i lm Pract ica l Course

    WORKSHOP ACTIVITY #7Corona Treatment

    CONCLUSION & RECOMMENDATIONS

    INSTRUCTORS COMMENTS

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    TRAINEES GRADE

    FOR THIS ACTIVITY

    ________________________

    INSTRUCTORS SIGNATURE

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 3 of 3 Page 3 of 3 Page 3 of 3 Page 3 of 3

    DATE: __________________

    DATE: __________________

    ________________________

    TRAINEES SIGNATURE

  • Page 48

    Workbook for Blown F i lm Pract ica l Course

    THEORETICAL BACKGROUND

    Rotary Printingis a printing technique in which the impressions are

    carved on a rubber plate and stuck on a cylinder, or carved on the cylinder

    itself, so that the printing can be done on long continuous rolls of paper,

    cardboard, plastic, or a large number of other substrate.

    Often Used Printing Processes for Blown Film:

    Flexographic Printing

    Rotogravure Printing

    FLEXOGRAPHIC PRINTING

    Flexographic printing has an advantage over rotogravure in that it can use a

    wider range of inks, water-based rather than oil-based inks, and is good at

    printing on a variety of different materials like plastics, foils, acetate films,

    brown paper, and other materials used in packaging. Typical products

    printed using flexography includes flexible packaging, including retail and

    shopping bags, food and hygiene bag, etc.

    A flexographic print is made by creating a positive mirrored master of the

    required image as a 3D relief in a rubber or polymer material. Flexographic

    plates can be created with analog and digital plate-making processes. The

    image areas are raised above the non-image areas on the rubber or polymer

    plate. The ink is transferred from the ink roll which is partially immerged in

    the ink tank. Then it transfers to the anilox roll (or meter roll) whose texture

    holds a specific amount of ink since it is covered with thousands of small

    wells or cups that enable it to meter ink to the printing plate in a uniform

    thickness evenly and quickly.

    WORKSHOP ACTIVITY #8

    Flexographic Printing

  • Page 49

    Workbook for Blown F i lm Pract ica l Course

    Theoretical Background continued

    PARTS OF A FLEXOGRAPHIC PRINTER

    WORKSHOP ACTIVITY #8Flexographic Printing

    Impression

    Cylinder

    Plate

    Cylinder

    Anilox

    Roller

    Fountain

    Roller

  • Page 50

    Workbook for Blown F i lm Pract ica l Course

    OBJECTIVES OF THE ACTIVITY

    1. To learn the basic operation of a flexographic printing machine for blown

    film

    2. To know the parts and functions of a flexographic printing machine

    PROCEDURE

    1. Pre-heat a blown film machine that has in-line flexographic printing

    machine.

    2. Prepare a rubber clich for flexographic film print run and the schematic

    drawing of a flexographic printing machine.

    3. Mount the rubber plate on the plate cylinder. Make sure of the alignment

    by following the groove etched on the cylinder surface. See the drawing.

    4. Move gear 1 (for Roll 1) towards gear 2 (for Roll 2) and mesh their teeth

    by about 3mm by turning knob C clockwise.

    5. Pour ink in the ink pan. Ink level at least a few millimetre of the fountain

    roller lower portion.

    6. Switch-on the printing drive.

    WORKSHOP ACTIVITY #8Flexographic Printing

  • Page 51

    Workbook for Blown F i lm Pract ica l Course

    Procedure continued

    7. Move the fountain roller 3 towards the anilox roller 4 by turning knob A

    clockwise. Observe the ink between these rollers. Putting more pressure

    between roller 3 and 4 means reducing the ink on the anilox concave

    surface and lesser ink will be transferred to the rubber plate.

    8. Move carriage of 3 & 4 towards 1 by turning the knob B until ink from

    the anilox is transferred to the rubber plate.

    9. Activate the pneumatic cylinder for the carriage D and observe the

    printing on the film.

    10. If print does not appear yet, turn knob C slower clockwise until print

    appears.

    10. When you feel you have attained the best print, take a sample printed

    film and cut the printed portion.

    11. Attach the printed film in your data sheet.

    WORKSHOP ACTIVITY #8Flexographic Printing

    Note:

    Each of the specific knobs has to be adjusted to attain

    a good ink tone balance and better quality print.

  • Page 52

    DATA SHEET ACTIVITY #8Flexographic Printing

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 1 of 3 Page 1 of 3 Page 1 of 3 Page 1 of 3

    ATTACH ATTACH ATTACH ATTACH

    YOUR YOUR YOUR YOUR

    PRINTED FILM PRINTED FILM PRINTED FILM PRINTED FILM

    HERE!HERE!HERE!HERE!

    FLEXOGRAPHIC PRINTED FILM

    1. When you pressed the fountain roller with the anilox roller, does this

    mean we are reducing the ink being transferred to the printing plate?

    2. What is the function of knob A?

    3. When you pressed carriage 3 & 4 to roller 1, did the image appear on the

    film?

    4. What is the function of knob B?

    YESYESYESYES NONONONO

    YESYESYESYES NONONONO

  • Page 53

    Workbook for Blown F i lm Pract ica l Course

    QUESTIONS & EXERCISES

    Choose correct answer.

    1. Which type of printing is done on polyethylene blown film?

    a. Screen printing

    b. Rotogravure printing

    c. Laser printing

    d. Flexographic printing

    2. Which process is done before printing the polyethylene film?

    a. Heat treatment

    b. Chemical treatment

    c. Corona treatment

    d. Laser treatment

    3. Why do plastics surfaces require pre-treatment for printing?

    a. To make plastic thicker

    b. To make plastic stronger

    c. To make plastic more decorative

    d. To make strong ink bonding on surface

    4. What type of chemical (thinner) is used to make printing ink thin and

    dryable during flexographic printing?

    a. Acid

    b. Kerosene

    c. Petrol

    d. Alcohol

    5. What is that rubber-like material we use in flexographic in making a

    printing plate?

    a. PVC

    b. Photopolymer

    c. Polyethylene

    d. None of these

    WORKSHOP ACTIVITY #8Flexographic Printing

    Cut R

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    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 2 of 3 Page 2 of 3 Page 2 of 3 Page 2 of 3

  • Page 54

    Workbook for Blown F i lm Pract ica l Course

    WORKSHOP ACTIVITY #8Flexographic Printing

    CONCLUSION & RECOMMENDATIONS

    INSTRUCTORS COMMENTS

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    TRAINEES GRADE

    FOR THIS ACTIVITY

    ________________________

    INSTRUCTORS SIGNATURE

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 3 of 3 Page 3 of 3 Page 3 of 3 Page 3 of 3

    DATE: __________________

    DATE: __________________

    ________________________

    TRAINEES SIGNATURE

  • Page 55

    Workbook for Blown F i lm Pract ica l Course

    THEORETICAL BACKGROUND

    Every day, our lives are touched by plastics packaging

    products. Polyethylene bag is one of the best applications of packaging

    products.

    Polyethylene bag is used for various purposes like shopping, grocery,

    laundry, food packaging, garments, textiles, agriculture, industrial products

    packaging, garbage, waste management, etc.

    There are mainly two types of methods to make polyethylene bags.

    Bottom sealed bag

    Top and bottom sealed bag

    WORKSHOP ACTIVITY #9

    Bag Making

    Examples of Bottom Sealed Bag Products

    Examples of Top and Bottom Sealed Bag Products

  • Page 56

    Workbook for Blown F i lm Pract ica l Course

    Theoretical Background continued

    WORKSHOP ACTIVITY #9Bag Making

    BOTTOM SEALING DIAGRAM

    BOTTOM SEALING PROCESS FLOW

  • Page 57

    Workbook for Blown F i lm Pract ica l Course

    Theoretical Background continued

    WORKSHOP ACTIVITY #9Bag Making

    DOUBLE SEALING DIAGRAM

    DOUBLE SEALING PROCESS FLOW

  • Page 58

    Workbook for Blown F i lm Pract ica l Course

    Theoretical Background continued

    WORKSHOP ACTIVITY #9Bag Making

    TYPES OF BAGS

    EXAMPLES OF BAG MAKING PRODUCTS

  • Page 59

    Workbook for Blown F i lm Pract ica l Course

    OBJECTIVES OF THE ACTIVITY

    1. To learn making polyethylene poly bags for various applications

    2. To learn the proper adjustment of sealing temperature to come up

    with acceptable product

    3. To determine the effect of product type on the production output rate

    PROCEDURE

    PART ISealing Temperature for LDPE and HDPE Bags

    1. Familiarize yourself with the bag making machine assigned to you by

    your Instructor.

    2. Determine the effect of changing the sealing temperature to final product

    by changing the temperature setting.

    3. Make 5 trials with 5 different temperatures using LDPE film.

    4. Each time you change the temperature, record the bag cutting speed and

    inspect the product if acceptable or not.

    5. Record all your data in your data sheet.

    6. Do the same for HDPE film.

    PART IIProduction Output

    1. Run five (5) different bag products (different sizes and materials) at

    constant speed using the machine assigned to you by your Instructor.

    2. For each run, record the bag cutting speed and the production output

    (bags/min).

    3. Record all your data in your data sheet.

    WORKSHOP ACTIVITY #9Bag Making

  • Page 60

    DATA SHEET

    PART ISealing Temperature for LDPE and HDPE Bags

    SEALING TEMPERATURE FOR LDPE BAGS

    ACTIVITY #9Bag Making

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 1 of 4 Page 1 of 4 Page 1 of 4 Page 1 of 4

    Trial No.

    Sealing Temperature

    Bag Cutting Speed Sealing Quality

    1

    2

    3

    4

    5

    acceptedacceptedacceptedaccepted rejectedrejectedrejectedrejected

    acceptedacceptedacceptedaccepted rejectedrejectedrejectedrejected

    acceptedacceptedacceptedaccepted rejectedrejectedrejectedrejected

    acceptedacceptedacceptedaccepted rejectedrejectedrejectedrejected

    acceptedacceptedacceptedaccepted rejectedrejectedrejectedrejected

    Trial No.

    Sealing Temperature

    Bag Cutting Speed Sealing Quality

    1

    2

    3

    4

    5

    acceptedacceptedacceptedaccepted rejectedrejectedrejectedrejected

    acceptedacceptedacceptedaccepted rejectedrejectedrejectedrejected

    acceptedacceptedacceptedaccepted rejectedrejectedrejectedrejected

    acceptedacceptedacceptedaccepted rejectedrejectedrejectedrejected

    acceptedacceptedacceptedaccepted rejectedrejectedrejectedrejected

    SEALING TEMPERATURE FOR HDPE BAGS

  • Page 61

    DATA SHEET

    PART IIProduction Output

    ACTIVITY #9Bag Making

    TRAINEE NAME GROUP NO.

    Cut R

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    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 2 of 4 Page 2 of 4 Page 2 of 4 Page 2 of 4

    Trial Trial Trial Trial No.No.No.No.

    MaterialMaterialMaterialMaterial Bag Size Bag Size Bag Size Bag Size (length)(length)(length)(length)

    Bag Cutting Bag Cutting Bag Cutting Bag Cutting SpeedSpeedSpeedSpeed

    Product RateProduct RateProduct RateProduct Rate (bags/min)(bags/min)(bags/min)(bags/min)

    1111

    2222

    3333

    4444

    5555

  • Page 62

    Workbook for Blown F i lm Pract ica l Course

    QUESTIONS & EXERCISES

    1. Which of these three are the bottom seal and the top & bottom seal bag?

    ____________ is the bottom seal bag.

    ____________ is the top & bottom seal bag.

    2. In the given drawing, why did they call this a top and bottom sealing?

    Explain briefly.

    ___________________________

    ___________________________

    ___________________________

    ___________________________

    ___________________________

    ___________________________

    ___________________________

    ___________________________

    3. Give at least two applications of this top & bottom sealed bags.

    Clue: bags that can be found in a market.

    Applications: _______________________________

    _______________________________

    WORKSHOP ACTIVITY #9Bag Making

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 3 of 4 Page 3 of 4 Page 3 of 4 Page 3 of 4

  • Page 63

    Workbook for Blown F i lm Pract ica l Course

    CONCLUSION & RECOMMENDATIONS

    INSTRUCTORS COMMENTS

    WORKSHOP ACTIVITY #9Bag Making

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    TRAINEES GRADE

    FOR THIS ACTIVITY

    ________________________

    INSTRUCTORS SIGNATURE

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 4 of 4 Page 4 of 4 Page 4 of 4 Page 4 of 4

    DATE: __________________

    DATE: __________________

    ________________________

    TRAINEES SIGNATURE

  • Page 64

    Workbook for Blown F i lm Pract ica l Course

    THEORETICAL BACKGROUND

    Recycling Procedure for Polyethylene Film

    WORKSHOP ACTIVITY #10

    Polyethylene Film Recycling

    1. Start machine heat-up. Set the temperature according to the required set-ting for the type of material to be recycled.

    2. Check the cooling water supply in/out and ensure that it is ON.

    3. Set the shredder temperature at 60C initially, then increase up to 100C, as temperature increases after shredder start.

    4. Start feeding scraps in shredder drum, ensuring that no metal or foreign matter is present. Set shredder speed to 45rpm maximum. The load must not exceed 22amps.

    Scrap MaterialScrap MaterialScrap MaterialScrap Material LDPELDPELDPELDPE LLDPELLDPELLDPELLDPE HDPEHDPEHDPEHDPE

    Temperature Settings Temperature Settings Temperature Settings Temperature Settings C 180 180 180 180 ---- 200 200 200 200 190 190 190 190 ---- 210 210 210 210 195 195 195 195 ---- 220 220 220 220

    OUTOUTOUTOUT ININININ

    Shredder Shredder Shredder Shredder TemperatureTemperatureTemperatureTemperature

    Speed Speed Speed Speed ControlControlControlControl

  • Page 65

    Workbook for Blown F i lm Pract ica l Course

    Theoretical Background continued

    WORKSHOP ACTIVITY #10Polyethylene Film Recycling

    5. After reaching to the set barrel temperature, clean the screen or change if required and check breaker plate also.

    6. Connect conveyor to the shredder and after ensuring metal detector is functioning, put conveyor in auto mode. Also connect the cooling water chamber to die-face cutter and tighten the screw properly.

    7. When shedder drum temperature reaches 90C, and barrel temperature, 185C to 220C, start oil pump, water pump, vibrator, blowers, and cen-trifuge.

    Screen CleaningScreen CleaningScreen CleaningScreen Cleaning Screen Change ControlsScreen Change ControlsScreen Change ControlsScreen Change Controls

    Up/DownUp/DownUp/DownUp/Down

  • Page 66

    Workbook for Blown F i lm Pract ica l Course

    Theoretical Background continued

    WORKSHOP ACTIVITY #10Polyethylene Film Recycling

    8. Start die face cutter and set speed to 1500 initially. Increase die face cut-ter speed in order to maintain pellet size of 2mm. Monitor the size of pellets and adjust the speed when needed.

    9. Start extruder at 25 rpm initially, then increase gradually up to 45 rpm. Observe the ampere meter to control motor load (max 40 amps).

    10. Observe smooth operation.

    Variable Speed Variable Speed Variable Speed Variable Speed

    ControlControlControlControl

    Extruder Speed Extruder Speed Extruder Speed Extruder Speed

    SettingSettingSettingSetting

    Extruder Amps Extruder Amps Extruder Amps Extruder Amps

    MeterMeterMeterMeter

  • Page 67

    Workbook for Blown F i lm Pract ica l Course

    OBJECTIVES OF THE ACTIVITY

    1. To learn recycling machine operation

    PROCEDURE

    .Observe the recycling machine start up procedure and write start-up steps in

    the given work sheet.(worksheet#9.1)

    Write your observations and fill data in process parameter sheet

    ( work sheet #9.2)

    PART IRecycling Machine Startup Procedure

    1. Observe the startup procedure for the recycling machine as performed by

    your Instructor.

    2. In your data sheet, write down the steps on the table provided.

    PART IIRecycling Machine Process Parameters

    1. Observe the actual recycling run for different plastics materials.

    2. Use the Process Monitoring Sheet provided in your data sheet to record

    your data on the actual machine run.

    WORKSHOP ACTIVITY #10Polyethylene Film Recycling

  • Page 68

    DATA SHEET

    PART IRecycling Machine Startup Procedure

    ACTIVITY #10Polyethylene Film Recycling

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 1 of 4 Page 1 of 4 Page 1 of 4 Page 1 of 4

    START PROCEDURE STEP OBSERVED

    1.

    2.

    3.

    4.

    5.

    6.

    7.

    8.

    9.

    10.

    11.

  • Page 69

    DATA SHEET

    PART IIRecycling Machine Process Parameters

    ACTIVITY #10Polyethylene Film Recycling

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 2 of 4 Page 2 of 4 Page 2 of 4 Page 2 of 4

    SCRAP MATERIALS

    LLDPE LDPE HDPE

    Barre

    l Temperature

    Cylinder 1

    Cylinder 2

    Cylinder 3

    Cylinder 4

    Joint

    Filter

    Die

    Shredder Tempera-ture

    Shredder Speed

    Shredder Motor Load (Amps)

    Extruder Speed

    Extruder Motor Load (Amps)

    Cutting Speed

    PROCESS PARAMETERS

    Process Monitoring SheetRecycling Machine

  • Page 70

    Workbook for Blown F i lm Pract ica l Course

    QUESTIONS & EXERCISES

    Choose correct answer.

    1. What are the advantages of recycling plastics?

    a. By recycling we can make more plastics

    b. Making plastics cheaper

    c. Recycling machinery business can grow up

    d. Reduce the consumption of energy and less pollution

    2. What is the STANDARD MARKING CODE for HDPE?

    3. Why are STANDARD MARKING CODES developed?

    a. To identify the strength of each plastics

    b. To identify the cost of each plastics

    c. To understand the number of times the plastics can be recycled

    d. To help consumers identify and sort the main types of plastic

    4. What is the consumption of plastics in packaging industries?

    5. What is the importance of oil circulation in the gear box of the extruder?

    a. To provide lubrication and reduce friction

    b. To increase the speed of an extruder

    c. To save power consumption of machine

    d. For cooling the gear box

    6. Select the barrel temperature (C ) range for HDPE scrap material

    a. 195, 200, 205, 210, 215, 220, 225

    b. 165, 170, 175, 180, 185, 190, 195

    c. 175, 180, 185, 190, 195, 200, 205

    d. 170, 180, 180, 187, 190, 190, 195

    7. Why is a metal detector provided on the conveyor?

    a. To sense metal and allow it to go into the shredder and extruder

    b. To sense metal and save the extruder from damage

    c. To measure the weight of plastics fed into the shredder

    d. To avoid dust to go inside

    8. How do you increase or decrease the size of plastics pallets?

    a. By adding or reducing material to the shredder

    b. By increasing or decreasing the barrel temperature

    c. By increasing or decreasing the speed of die face cutter

    d. By increasing or decreasing cooling temperature

    WORKSHOP ACTIVITY #10Polyethylene Film Recycling

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 3 of 4 Page 3 of 4 Page 3 of 4 Page 3 of 4

    a. c. d. b.

    a. 35% c. 30% d. 15% b. 25%

  • Page 71

    Workbook for Blown F i lm Pract ica l Course

    CONCLUSION & RECOMMENDATIONS

    INSTRUCTORS COMMENTS

    WORKSHOP ACTIVITY #10Polyethylene Film Recycling

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    TRAINEES GRADE

    FOR THIS ACTIVITY

    ________________________

    INSTRUCTORS SIGNATURE

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 4 of 4 Page 4 of 4 Page 4 of 4 Page 4 of 4

    DATE: __________________

    DATE: __________________

    ________________________

    TRAINEES SIGNATURE

  • Page 72

    Workbook for Blown F i lm Pract ica l Course

    PRACTICE YOUR OPERATIONS SKILLS!

    1. Now that you have learned the basics of the Blown Film Extrusion

    process, it is time to practice your skills in running the plant and

    producing acceptable products.

    2. Strictly follow the Standard Operating Procedures (SOP) for each

    plant operations that you are going to perform.

    3. Use the worksheet tables and forms in the next pages to record your

    data.

    4. After each practice operations, write your general comment on the

    how well you have done your practice in the Conclusion &

    Recommendations page.

    5. Write down what you have done well, and what you should improve

    for the next practice.

    6. Enjoy practicing while being safe!

    WORKSHOP ACTIVITY #11-13

    Practice Plant Operations

  • Page 73

    Workbook for Blown F i lm Pract ica l Course

    STANDARD OPERATING PROCEDURES (SOP)

    PART ASOP for Plant Run Preparations

    1. Read and understand carefully the JOB INSTRUCTIONS given by

    your instructor. (See Job Instruction #1).

    2. Switch on main power and pre-heat the blown film machine

    according to the temperature listed in the Job Instruction.

    3. Check the condition of the following:

    Chilled water for barrel and reduction gear cooling (optional).

    Air supply for downstream equipments like nip rolls, winder and

    pressure roll.

    4. Prepare the materials to be used according to the Job Instruction.

    5. Prepare the following tools and equipments:

    6. Prepare bobbins according to the width of the roll to be produced.

    7. Set the bobbin to the shafts of the winder and wrap around adhesive

    tape with the sticky surface exposed. Two turns are enough just to

    stick the film during change roll. Have at least five bobbins for

    replacements during roll change.

    8. Prepare the guide twine to the web path from the die to winder.

    9. Fill the hopper with the required materials.

    10. Change the screen in the screen changer if necessary.

    WORKSHOP ACTIVITY #11-13Practice Plant Operations

    Dial thickness gauge

    Tape measure

    Cutting knife for film

    Silicon spray

    Cotton rags for die cleaning

    Guide twine or flat rope

    Allen wrench for die adjust-

    ment

    Cotton Gloves

    Brass or copper spatula

    Scouring paste

    Scouring pad

  • Page 74

    Workbook for Blown F i lm Pract ica l Course

    Standard Operating Procedures continued

    11. Check the following blown film major parts conditions:

    Sizing basket up and down movement

    Haul-off unit roll rotation and air pressure and functions

    Collapsing device functional adjustments

    Corona treater if flexo printing will run

    Printing unit functional adjustments and rolls rotations

    Winder air pressure required for pressure roll and test for roll

    change

    11. Wait for 1.5 hours till the ready indicator light lights up and verify

    again the temperature settings if the actual display temperatures

    correspond to the set temperatures. If yes, machine is ready to run. If

    not, check settings. If actual temperature is low, extend preheating

    time.

    PART BSOP Startup

    1. Open the shutter of the hopper.

    2. Switch-on the main motor and adjust the screw rpm to 10.

    3. Caution: Avoid facing the die during this stage. Melt material may

    spurt-out.

    4. Remove the initial extruded melt. This contains air trap in a material

    that should be removed.

    5. Increase screw speed to 30 rpm and remove the molten materials in

    the die. Wait until the high melt pressure drops.

    6. Do item 5 for 50, 75, and 100 rpm and back to 0.

    7. Clean the die and the die lip using scouring pad and scouring paste.

    8. Check die gap alignment. Align if off-centered by loosening and

    tightening centering screws. Use Allen wrench for adjusting the

    screws.

    WORKSHOP ACTIVITY #11-13Practice Plant Operations

  • Page 75

    Workbook for Blown F i lm Pract ica l Course

    Standard Operating Procedures continued

    9. Open the blower damper at 30 degrees. Minimal air blown at the

    film for initial start.

    10. Open compressed air supply for inflating the bubble at minimum

    only.

    11. Make a loop on the film guide twine and have it ready.

    12. Switch-on again the main motor and set the screw speed to 25 rpm.

    13. Switch-on the haul-off nip and set the nip roll speed to 6-8 rpm.

    14. As the melt comes out let it cool to solidify and tie the film guide

    twine loop on that cooled lump.

    15. Pull gently the melt as it continue forming into a bubble.

    16. After the solid lump passes between the nip rolls, close the nip roll

    and let it do the pulling of the bubble.

    17. Temporarily closed the compressed air.

    18. Just pull the flat tube gently till it reaches the printing unit.

    19. Using the cutting knife, cut diagonally the film to make a pointed

    end.

    20. Insert this pointed end between the plate and impression roller of the

    printer.

    21. Pass the film between the open pressure roll and winder roll.

    22. Close the pressure roll pinching the film.

    23. Immediately, start the winder. Set minimum winding tension.

    24. Insert the film in between the rotating winder roller and bobbin with

    caution and start winding the film.

    25. Increase screw rpm gradually to the target rpm. (See Job Instruction.)

    26. Increase bubble diameter to its required lay-flat tube width. (See Job

    Instruction.)

    27. Increase nip roll speed according to the required film thickness. (See

    Job Instruction.)

    28. Switch-on corona treater if printing unit will run.

    WORKSHOP ACTIVITY #11-13Practice Plant Operations

  • Page 76

    Workbook for Blown F i lm Pract ica l Course

    Standard Operating Procedures continued

    PART CSOP for Shutdown

    1. Close the shutter of the hopper.

    2. Switch-off corona treater if printing unit is running.

    3. Wait till the bubble starts to rattle. It is better to have a little material

    inside the barrel and die to seal-off the barrel form air getting inside.

    4. Gradually bring down the screw speed to 0 rpm.

    5. Switch-off the main motor.

    6. Bring down nip roll speed to 0 and switch-off.

    7. Open the nip roll.

    8. Bring down winder speed to 0 and switch-off.

    9. Open the pressure roll.

    10. Close the chilled water supply valve.

    11. Start lowering the temperature for 30 minutes.

    12. Switch-off the main power.

    13. Bring good rolls to the bag making area. Record the total roll weight

    produced in the Job Instruction.

    14. Bring all scrap to the recycling area. Record the total weight of the

    scrap in the Job Instruction.

    15. Return all tools and equipment to their proper places.

    16. Fill-up all the information needed in the Job Instruction.

    17. Submit the Job Instruction to your instructor.

    WORKSHOP ACTIVITY #11-13Practice Plant Operations

  • Page 77

    DATA SHEET

    BLOWN FILM EXTRUSION PRODUCTION REPORT

    ACTIVITY #11Practice Plant Operations (LDPE)

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 1 of 4 Page 1 of 4 Page 1 of 4 Page 1 of 4

    No. Type Resin Name / Grade Blending Ratio (%)

    1

    2

    Material Specifications

    Machine Running Condition Monitoring

    1. 2. 3.

    Actu

    al T

    emperature ( oC

    )

    Heater Zone 1.1

    Heater Zone 1.2

    Heater Zone 1.3

    Heater Zone 2.1

    Heater Zone 2.2

    Heater Zone 3.1

    Heater Zone 3.2

    Heater Zone 3.3

    Heater Zone 3.4

    Heater Zone 4.1

    MT

    Extruder Screw Speed (rpm)

    Extruder Melt Pressure (bar)

    Air Ring Pressure (KPa)

    Temperature (oC)

    Haul-off Speed (mpm)

    Corona Treater Power (%)

    Printing Unit Motor Load (%)

    Winder Tension (N)

    Lay-on Pressure (bar)

    Contact Pressure (bar)

    Lot Number 4.

    5.

    Machine No.

    Date:

    Product Description:

  • Page 78

    DATA SHEET

    BLOWN FILM EXTRUSION PRODUCTION REPORT continued

    ACTIVITY #11Practice Plant Operations (LDPE)

    TRAINEE NAME GROUP NO.

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 2 of 4 Page 2 of 4 Page 2 of 4 Page 2 of 4

    Output Monitoring

    Quality Check Monitoring

    Roll Number

    Thick

    ness P

    rofile

    (m)

    Measuring Point 1

    Measuring Point 2

    Measuring Point 3

    Measuring Point 4

    Measuring Point 5

    Measuring Point 6

    Measuring Point 7

    Measuring Point 8

    Average Thickness (m)

    Lay Flat Width (mm)

    Gusseted LFW (mm)

    Left Gusset Width (mm)

    Right Gusset Width (mm)

    Treating Level (OK/NOK)

    Tape Test (OK/NOK)

    Print Centering (OK/NOK)

    Print Repeat Length (mm)

    Clarity (OK/NOK)

    Color (OK/NOK)

    Defects (W/WO)

    Roll Disposition

    (Pass / Reject / On-Hold)

    Lot Number 1. 2. 3. 4. 5.

    Dismount Time

    Roll Number

    Length (m)

    Weight (kg)

    Total Scrap Weight (kg)

  • Page 79

    Workbook for Blown F i lm Pract ica l Course

    QUESTIONS & EXERCISES

    1. If you want to raise the frost line height, what part of the machine are

    you going to adjust?

    a. winder tension

    b. the haul-off

    c. Air adjusting ring

    2. If you want to decrease the film thickness, what control are you going

    to adjust?

    a. haul-off speed

    b. winder speed

    c. main motor speed

    3. How are you going to adjust the speed in question #2?

    a. increase speed

    b. decrease speed

    4. If you want to reduce the lay-flat width, what are you going to do

    with the bubble?

    a. increase air inside

    b. decrease air inside

    5. How are you going to increase or decrease the air inside the bubble?

    Describe in your own words.

    ______________________________________________________

    ______________________________________________________

    6. Is it necessary to use a film guide twine during start-up? Why?

    ______________________________________________________

    ______________________________________________________

    7. Give at least 3 important speed adjusting controls of the blown film

    control panel.

    _________________________________________________

    _________________________________________________

    _________________________________________________

    WORKSHOP ACTIVITY #11Practice Plant Operations (LDPE)

    Cut R

    eport F

    orm

    and Submit to

    Instru

    ctor

    Report Form Report Form Report Form Report Form ---- Page 3 of 4 Page 3 of 4 Page 3 of 4 Page 3 of 4

  • Page 80

    Workbook for Blown F i lm Pract ica l Course

    CONCLUSION & RECOMMENDATIONS

    INSTRUCTORS COMMENTS

    WORKSHOP ACTIVITY #11Practice Plant Operations (LDPE)

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________________________________________________________

    ___________