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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
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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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Page 10
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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Page 11
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
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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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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Page 16
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
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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
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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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Page 24
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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Page 26
Workbook for Blown F i lm Pract ica l Course
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.
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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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Page 29
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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Workbook for Blown F i lm Pract ica l Course
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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Workbook for Blown F i lm Pract ica l Course
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
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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
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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
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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
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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
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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
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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.
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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
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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
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
B. How do you decrease the width of lay flat tube?
C. How do you increase the thickness of the film?
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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
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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
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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
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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
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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?
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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
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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
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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
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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
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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
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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.
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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
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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
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 #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
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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
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Workbook for Blown F i lm Pract ica l Course
Theoretical Background continued
WORKSHOP ACTIVITY #9Bag Making
BOTTOM SEALING DIAGRAM
BOTTOM SEALING PROCESS FLOW
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Workbook for Blown F i lm Pract ica l Course
Theoretical Background continued
WORKSHOP ACTIVITY #9Bag Making
DOUBLE SEALING DIAGRAM
DOUBLE SEALING PROCESS FLOW
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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
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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
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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
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DATA SHEET
PART IIProduction Output
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 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
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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
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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
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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
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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
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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
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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
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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.
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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
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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%
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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
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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
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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
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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
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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
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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
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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:
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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)
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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
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Page 80
Workbook for Blown F i lm Pract ica l Course
CONCLUSION & RECOMMENDATIONS
INSTRUCTORS COMMENTS
WORKSHOP ACTIVITY #11Practice Plant Operations (LDPE)
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
___________________________________________________________
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