Download Handbook of troubleshooting plastics processes : a practical guide

Handbook of
Troubleshooting
Plastics Processes
A Practical Guide
Edited
John
R.
by
Wagner, Jr.
-/>
Scrivener
©WILEY
Contents
Preface
xvii
List of Contributors
Part 1:
1
xix
Troubleshooting
The Economics of
Basics
l
Troubleshooting Polymer Processing Systems
3
Mark D. Wetzel
1.1
Introduction
3
1.2
Economic Incentives and Necessities
4
1.3
Troubleshooting
Managing
Troubleshooting Techniques
1.6
Case Histories
14
1.6.1
14
1.6.3
1.7
Resources and Costs
11
and Their Relative Costs
Single Screw Extrusion Instability
Compounding Extruder Catastrophic Failure
Polymer Degradation During Melt Processing
Conclusions
12
14
16
20
References
20
Troubleshooting Philosophy
John R. Wagner, Jr.
21
2.1
21
Introduction
2.2
Troubleshooting Methodology
Bibliography
3
(->
1.5
1.6.2
2
Resources and Their Cost
1.4
Statistical Tools for Trouble
Shooting
23
25
a
Process
27
Vincent Vezza
3.1
Introduction
3.2
Basic
3.3
3.4
27
Statistical Concepts
3.2.1
Histogram
3.2.2
Scatter
Diagram
Mean and Standard Deviation
Sample
Design of Experiments (DOE)
3.4.1
Factorial Design
3.4.2
Fractional Factorial Design
Capability
3.5
Process
3.6
Control Charts
28
28
28
29
31
31
34
37
38
3.7.1
Central Limit Theorem
39
3.7.2
Variable Data Control Charts
41
3.7.3
Control Charts for Attribute Data
43
v
vi
Contents
References
45
Bibliography
45
Statistics
Design
of
45
45
Experiments
Statistical Process Control
45
Part 2: Extrusion Processes
47
Single Screw Extrusion
John R. Wagner, Jr.
49
4.1
Introduction
49
4.2
Process
51
5
References
54
Troubleshooting the Co-rotating Fully Intermeshing Twin-screw Compounding System
Paul Andersen, Rich Kanarski and John R. Wagner, Jr.
57
5.1
Introduction
57
5.2
Equipment Description
58
5.3
Troubleshooting
59
5.3.1
60
5.4
5.5
5.6
6
Description
What is
Troubleshooting?
Tools of the Successful Troubleshooter
60
5.4.1
Experience
60
5.4.2
Vent Flow Problem
61
Product, Process and Equipment Knowledge
62
5.5.1
High Discharge
64
5.5.2
Barrel
Pressure Problem
Temperatures Higher
than Set Points Problem
Climbing Discharge Temperature
5.5.4
Gels and Un-melts in the Extrudate Problem
65
5.5.5
Holes
65
5.5.6
Process
or
Problem
65
5.5.3
Bubbles in the Extrudate Problem
Surging
Problem
65
66
Conclusion
66
References
67
Troubleshooting for Injection Molding
69
James J.
6.1
Wenskus
Introduction
6.1.1
69
The Basic
Approach
6.2
Understanding Temperature
6.3
Product Shift to
6.4
a
70
Control
Different Machine
6.3.1
Calculate the New Pressure
6.3.2
Procedure
Settings
70
72
72
73
Part
74
6.4.1
Weight as an Analytical Tool
Example Part Weight for Process Variability Analysis
6.4.2
Long Term Variability Analysis
6.4.3
Short Term Variability Analysis
75
6.4.4
6.4.5
-
4
Variability
Process Benchmarking
Evaluation
76
76
76
for
Quality
77
6.4.6
Benchmark Evaluation
78
6.4.7
Summary
79
Contents
6.5
Part
Weight as
Unconstrained Process
6.5.2
Partially
6.5.3
Constrained Process
6.5.4
Warpage
7
80
Constrained Process
81
82
82
Relationship
Determining
79
Control
Aimpoint
6.5.1
6.5.5
6.6
Dimensional
vii
of Shot
Weight and Hydraulic
Pressure
84
85
the Gate Freeze-Off Time
6.6.1
Procedure to Determine the Freeze-Off Point
86
6.6.2
Time
Analysis
86
6.6.3
Pressure Procedure
86
References
88
Blown Film
89
Karen Xiao and Steve Gammell
7.1
Introduction
89
7.2
Process
92
7.2.1
Extruders
94
7.2.2
Dies
94
7.2.3
Process
97
Cooling
The Bubble Collapsing Process
Haul-Off/Primary Nip
Film Winding
7.2.4
7.2.5
7.2.6
7.3
7.4
Description
and
98
99
101
7.2.6.1
Center-drive Winder
102
7.2.6.2
Surface Winders
102
Special Tools for Troubleshooting
7.3.1
Winding Systems
105
Case Studies
109
108
7.4.1
Case Study 1: Carbon Buildup
109
7.4.2
Case
110
Study
2: Poor
Gauge Uniformity
111
References
8
Systems
Cast Film
113
Troubleshooting
Andrew W. Christie and Beth M. Foederer
8.1
Coextrusion Film
8.2
Troubleshooting
8.2.1
8.3
114
Method
The Problem Statement
115
The
115
Hypothesis
8.2.3
Testing the Hypothesis
8.2.4
Evaluating the Results
Common Problems, Hypotheses
8.2.2
113
Systems
116
117
and Tests
117
8.3.1
Gels in Film
117
8.3.2
Film
120
8.3.7
Clarity
Wrinkling
Inability to Reach Output
Poor Melt Mixing
Melt Temperature Too Low
Melt Temperature Too High
8.3.8
Extruder Power Insufficient
8.3.3
8.3.4
8.3.5
8.3.6
120
121
122
123
123
124
Contents
8.3.9
Film Streaks
8.3.10 Melt
Lines
or
Appearance
Thickness Variation
8.3.11
124
Defects
8.3.12 Thickness Variation
-
viii
-
125
Cross Direction
125
Machine Direction
126
8.3.13 Poor Wound Roll
126
8.3.14
127
Tear
Edge
Appearance
(Unstable Edges)
8.3.15 Pin Holes
127
8.3.16 Extruder
128
Surging
8.3.17 Draw Resonance
128
8.3.18 Film Discoloration
129
Poor Heat Seal
8.3.19
8.3.20 Odor
8.3.21
Flavor
-
Strength
129
Scalping
129
Poor
Strength
129
8.3.22 Film
Blocking
130
8.3.23 Poor
Printability
130
8.3.24 Camber
or
Curl
131
8.3.25 Scratches
131
References
Oriented
Eldridge
9.1
Films-Troubleshooting
M.
Mount,
and Characterization
133
III
Introduction
133
9.2
Process Overview: Biaxial Orientation
134
9.3
Oriented Film Markets
141
9.3.1
9.4
Oriented
BOPP
141
Polyester OPET
Polystyrene OPS
9.3.4
Oriented Polyamide (Nylon) OPA
Troubleshooting the Film Orientation Process
Polypropylene
OPP
or
9.3.2
Oriented
143
9.3.3
Oriented
144
145
as
Applied
to
OPP Films
9.4.1
Control Variables
9.4.2
Drying
Resin
9.4.1.2
Extrusion
9.4.1.3
Casting
9.4.1.4
Machine Direction Orientation
153
9.4.1.5
Transverse Direction Orientation
153
9.4.1.6
Web
156
9.4.1.7
Winding
Dependent
9.5
Special
9.6
Case Studies
9.6.2
146
9.4.1.1
146
147
and Pinning
Handling
149
and Surface Treatment
156
Noise Variables
9.4.3
9.6.1
146
Tools for
157
Variables
157
Troubleshooting
158
159
Limitation in PET Film Production
Casting Capacity
Floating Gauge Extrusion Instability
-
9
131
and MDO Heat Transfer
Limitations
9.6.3
Output
Limitation from
159
160
Coextrusionlnstability
162
References
164
Bibliography
164
Contents
10
Troubleshooting
the
Thermoforming
Process
ix
167
James L. Throne
10.1
General
10.2
Categorization of the Process
10.2.1
Thick-Gauge Process
10.2.2
Thin-Gauge Process
Specific Aspects of the Thermoforming
10.3
167
169
169
170
Process
172
172
10.3.2
Molds and Mold
173
10.3.4
Design
Incoming
Quality Issues
Materials Handling
Ingress
10.3.5
Heating
175
10.3.6
Pre-stretching (Plug Assist)
176
10.3.7
Pre-stretching (Vacuum/Air
10.3.9
10.3.10
10.3.11
10.3.12
10.3.13
10.3.14
Sheet
174
174
-
Pressure Formation)
the Mold
Contacting
Cooling and Rigidifying the Formed
Removing the Formed Part from the
Materials Handling
Egress
Part
177
Mold
178
178
Trimming
178
Post-trimming
Regrind
Issues
179
180
Solving Methodology
180
182
Trimming
General Preventative Maintenance
Concepts
183
10.5.1
Crisis Maintenance
184
10.5.2
Routine Maintenance
184
General Predictive Maintenance Concepts
187
10.7
Safety during Troubleshooting
10.7.1
Make-up of a Troubleshooting Team
1:
Appendix
Thermoforming References with Troubleshooting Sections
Appendix 2: Plastic Materials References
Appendix 3: Troubleshooting Guidelines for Thick-Gauge Thermoforming
Appendix 4: Troubleshooting Guidelines for Thin-Gauge Thermoforming
Appendix 5: Time-dependent Ranking of Typical Courses of Action
Appendix 6: Troubleshooting Guidelines for Trimming Parts
Thin-Gauge
Thick-Gauge
11
176
176
-
Problem
10.4.1
10.6
Thermoforming
Critical Material Issues
10.3.8
10.5
in
10.3.1
10.3.3
10.4
Concepts
188
192
193
193
194
199
209
210
210
213
Proper Equipment Processing for Industrial/Technical Blow Molding
217
Robert A. Slawska
11.1
Introduction of Blow
Blow Molded
How Parts
11.1.2
Positive Benefits of the Process
11.1.3
218
Molding
11.1.1
are
Factors of Accumulator Head Blow
218
219
Molding
219
11.2
Negative
Select the Proper Equipment
11.3
Extruder
222
11.4
Accumulator Head
225
11.5
Importance of Cleaning
226
220
x
12
Contents
11.6
Press
229
11.7
Hydraulics
230
11.8
Microprocessor
232
11.9
Pneumatic
Systems
233
11.10 Part Take Out
233
11.11
234
System
Selection of Equipment
PET Stretch Blow
237
Molding
Dan Weissmann
12.1
Introduction
237
12.2
The PET Universe
238
12.3
Technology History
239
12.4
PET
239
12.5
PET
12.6
Bottle Universe
Chemistry
Morphology
243
12.7
Bottle
12.8
Commercial
12.9
Process Elements
Manufacturing
Manufacturing
247
251
12.9.1.3
12.9.2
Molding
Hot Runner
12.9.3
251
254
Stresses
256
System
258
12.9.2.1
Gate Crystallinity and Separation
259
12.9.2.2
Gate Pin Holes
260
Mold
Blow
260
Cooling
12.9.3.1
12.9.4
251
Acetaldehyde
12.9.1.2
Preform Problem
Analysis
261
Molding
12.9.4.1
12.9.5
Preform
12.9.6
Blowing
Case
245
Processes
Injection Molding
12.9.1.1
IV Drop
12.9.1
12.10
241
261
General
Principles Reheating
Temperature Profiling
-
and Preform
Blow
12.9.6.1
Quality Attributes
12.9.6.2
Blow
and Performance Issues
Process
Molding
Monitoring
12.9.6.3
On Line Inspection
12.9.6.4
Testing and Test Procedures
12.9.6.5
Special Processes
Sample: Thermal Stability Failure of CSD Bottles
Molding
261
263
264
References
13
Temperature
266
269
271
271
272
277
278
Problems and Solutions
-
281
Norman C. Lee
13.1
Introduction
281
13.2
Troubleshooting
282
13.3
Variables
13.3.1
13.3.2
Affecting
the Blow
Molding Process
283
PARTI:
Defects in Article
284
13.3.1.1
PART I
284
-
Defect in Finished Article
PART II: Parison Defects
289
13.3.2.1
289
PART II
-
Defects of the Parison
Contents
13.4
13.3.3
Noise
293
13.3.4
Ambient Conditions
293
Preventative Maintenance
293
13.4.1
Maintenance Recommendations
293
13.4.2
Machine Check Out
294
13.5
Injection and Stretch Blow Molding
Computer Integrated Manufacturing (CIM)
Acknowledgement
Bibliography
13.6
14
xi
Extrusion
294
in Extrusion Blow
Molding
295
297
298
Coating Troubleshooting
299
Beth M. Foederer and Andrew W. Christie
14.1
Coextrusion Extrusion
14.2
Troubleshooting
14.3
Common
Coating/Laminating Systems
299
300
Method
Problems, Hypotheses and Tests
301
14.3.1
Gels in Film
301
14.3.2
Poor Adhesion
304
14.3.3
305
14.3.7
Wrinkling
Low Output
Poor Melt Mixing
Melt Temperature Too Low
Melt Temperature Too High
14.3.8
Extruder Power Insufficient
309
14.3.9
Die Lines
309
14.3.4
14.3.5
14.3.6
306
307
308
308
14.3.10
Melt Appearance Defects
309
14.3.11
Thickness Variation
Cross Direction
310
14.3.12
Thickness Variation
Machine Direction
310
14.3.13
Poor Wound Roll
14.3.14
Edge
14.3.15
Pin Holes
312
14.3.16
Extruder
312
14.3.17
Draw Resonance
312
14.3.18
PoorHeatseal
313
14.3.19
Odor
Flavor
313
14.3.20
Poor
14.3.21
Camber
14.3.22
Scratches
Tear
-
-
311
Appearance
(Unstable Edges)
311
Surging
-
Scalping
Printability
or
313
314
Curl
314
314
References
315
Part 3: Non-extrusion Processes
15
317
Adhesive and Thermal Lamination
Tom Dunn
15.1
317
Introduction
15.1.1
Process Overview
15.1.2
Markets Served
15.1.3
Historical and Future Growth
Challenges
and Threats
317
318
Projections
-
Technology
318
Contents
15.2
Process
15.2.1
15.2.2
15.2.3
319
Description
Major Process Components
Equipment Production Ranges
319
319
319
Manufacturers
15.3
Control Variables
320
15.4
Random Cause Variables
324
15.5
Dependent Variables
Special Tools for Troubleshooting
325
15.6
15.6.1
15.7
326
327
Product
328
Case Studies
15.7.1
15.7.2
Easy-peel
Spotty
or
328
Rip-off
330
Results
330
Bibliography
Troubleshooting
for
331
Rotomolding
Paul Nugent
The Basic Process
16.1
337
16.2.1
16.2.2
Colorants and Additives
339
16.2.3
Material Mixing
339
16.2.4
Molds and Fixtures
339
16.2.5
Machinery
340
16.2.6
Calibration
340
16.2.7
Production Process and Records
340
Preparation
Typical Rotomolding Problems
Typical Solutions
Adhesion Difficulty in Painting
16.4.1
-
16.4
336
Materials In-bound and Powder
343
347
or
Applying Labels
347
Around Inserts
347
Other Areas
348
16.4.2
Blowholes
16.4.3
Blowholes
16.4.4
Blowholes
16.4.5
Bubbles
16.4.6
Coining (Pockmarks)
350
16.4.7
Color
Part Burned/Discolored
350
16.4.8
Color
Static Swirl
351
16.4.9
Color
-
-
-
Parting
-
on
348
Line
Part Surface
or
in the Cross-section
349
352
Unevenness
Line
352
16.4.10
Flash at the
16.4.11
353
16.4.16
Foaming Coarse or Uneven Foam
Foaming Gaps in Wall Cross-section
Foaming Part Deformation
Incomplete Material Fusion
Incomplete Mold Fill (Bridging)
Low Impact Strength
16.4.17
Low Part Stiffness
356
16.4.18
357
16.4.19
Long Oven Cycle
Long-term Part Failure
16.4.20
Mold Distortion,
16.4.12
16.4.13
16.4.14
16.4.15
Parting
-
-
-
16.3
331
Key Quality Control Steps in Rotomolding
-
16.2
-
xii
Explosion
353
354
354
355
355
357
358
Contents
16.4.21
Plate Out
16.4.22
Sticking
16.4.23
Wall Thickness
16.4.24
Warpage
16.4.25
Whitish Part
358
in Mold
359
Uneven
360
Appearance
361
-
360
Plastics
Calendering
Chellappa Chandraseknran
17.1
xiii
363
Introduction
363
17.2
Blending
17.3
Mills and Strainers
365
17.4
Calender
365
17.5
General
17.9
17.10
of
a
Calendering
Machine
367
367
17.5.2
Sheet Finishes
368
17.5.3
Roll Contours
369
17.5.4
Frame
370
17.5.5
Roll Adjustment
370
17.5.6
Bed Plate
370
17.5.7
Lubrication
371
Temperature
Control
371
17.5.9
Safety and Safety Regulations
Calendering Process
17.6.1
Heating and Delivery to the Calender
372
The
372
17.6.2
Roll Banks
373
17.6.3
Sheet Takeoff and
Input
Embossing
and
Post-processing
Laminating
375
is Preferred to Extrusion
Process Variables
Calendering
17.9.1
Barring
374
375
The Formulas
Why Calendering
373
374
Materials and Products
17.7.1
17.8
Description
364
Rolls
17.6.4
17.7
Fluxing
17.5.1
17.5.8
17.6
and
377
and Noise Due to Roll Vibration
17.9.2
Machine
17.9.3
Product Variation
17.9.4
Overcoming
Dependent
and
Variable
Correcting
377
377
378
379
Process Variation
Conclusion
381
381
References
382
Bibliography
382
Compression Molding
383
Muralisrinivasan Natamai Subramanian
18.1
Introduction
383
18.2
Materials
384
18.2.1
Thermoplastics
18.2.2
Thermosets and
18.2.3
18.2.4
and
Compression Molding
Compression Molding
Premix or Prepreg Preparation
Fiber Alignment
384
385
386
386
xiv
Contents
18.2.5
18.2.6
18.3
Sheet
386
Pre-form
Prepreg
Molding Compound
18.3.1
386
386
Production
-
388
Mold
388
18.5
Technology Compression Molding
18.4.1
Important Variables during Processing
Troubleshooting
18.6
Problems and Solution(s)
392
18.7
Summary
393
18.4
-
389
390
18.7.1
Fundamentals
393
18.7.2
393
18.7.3
Advantages
Disadvantages
18.7.4
Future Trends
394
394
395
References
19
Transfer
397
Molding
Muralisrinivasan Natamai Subramanian
19.1
Introduction
397
19.2
Curing
398
19.3
Processing
399
19.4
Mold
400
19.5
Process
19.6
Method
19.7
Pot
400
Optimization
401
401
19.8
Molding
19.7.1
Plunger/Transfer Molding
19.7.2
Screw Type Transfer Molding
Screw Injection Type
19.7.3
Troubleshooting
19.9
Summary
404
19.9.1
Advantages
404
19.9.2
Disadvantages
404
19.9.3
Future Trends
405
19.9.4
Fundamentals
405
Type
Transfer
402
402
402
403
405
References
20
Pultrusion Process
Joseph
20.1
E. Sumerak
20.3
407
Introduction
20.1.1
20.2
407
Troubleshooting
Pultruded Products
are
Governed
by
a
Performance
Specification
409
Materials Review
410
20.2.1
Resin
410
20.2.2
Resin
20.2.3
Resin
20.2.4
Resin
20.2.5
Reinforcements
411
Reactivity
Reactivity
Viscosity
Measurement
414
415
416
Process Parameters
20.3.1
Composition and
412
Process
Specification
417
Contents
20.4
Manufacturing
20.4.1
20.5
417
Defects
417
Defects
Material Related Defects
419
20.5.1
Resin
419
20.5.2
Reinforcements
420
20.6
Process Parameter Related Defects
422
20.7
Methods Related Defects
42b
20.8
The
429
20.9
20.10
Troubleshooting
20.8.1
Subjective
20.8.2
Visual Tools
20.8.3
On-Line
20.8.4
Off-Line
Process
429
Objective
versus
430
Tools
Quantitative Analysis
Quality Assessment
Troubleshooting Examples
Summary
434
435
Tools
438
438
Acknowledgement
439
References
439
Troubleshooting Static Problems
Kelly Robinson
21.2
441
Introduction
21.1.1
Nature and Character of Static
441
21.1.2
Cost of Static Problems
442
Root Causes of Static
443
21.2.1
443
Tribocharging/Contact Charging
21.2.1.1
21.2.2
21.3
441
in Plastics Processes
444
Triboelectric Series
Triboelectric Series
21.2.3
Application of the
Charge Induction
21.2.4
Ionizer Imbalance (Active
445
446
446
Charging)
447
Static Measurement Tools
21.3.1
Electrostatic Fieldmeters (FMs) and
Non-Contacting
Electrostatic
447
Voltmeters (ESVMs)
21.3.1.1
Electrostatic Fieldmeters
Net
21.3.1.2
21.3.1.4
Fieldmeters
Respond
to
447
Charge
Non-contacting
Electrostatic Voltmeter
Voltmeters
448
to Surface
Charge
Spatial Resolution and Response Time
Typical Applications Monitor Static Performance
Respond
21.3.1.3
-
-
21.1
-
450
with
451
Fieldmeters and Voltmeters
21.3.2
Charge
Meter
-
21
xv
Coulomb Meters
are a
Direct Measure of
Charge
455
Principles of Operation
21.3.2.2
Typical Applications
Resistivity Meters
21.3.2.1
21.3.3
21.3.3.1
Resistivity
456
457
Meters
Resistivity Meters
Charge Dissipation Time Measurements
21.3.4.1
Importance of Charge Dissipation Time
21.3.4.2
Principles of Operation Static Dissipation Time
21.3.4.3
Typical Application Static Dissipation Time
21.3.3.2
21.3.4
Volumetric
Surface
-
-
455
457
460
463
463
463
464
xvi
Contents
21.4
21.5
Static Problem Diagnosis
464
21.4.1
Understand the Problem
464
21.4.2
Baseline Data and Control Charts
465
21.4.3
Hot Rolls
467
21.4.4
Static
Specifications
469
Problems
470
Solving Static
21.5.1
Locate the Source of
471
21.5.1.1
Charge Separation
Unwinding Roll
471
21.5.1.2
Drive Roller
472
21.5.1.3
Coater
21.5.1.4
21.5.1.5
21.5.1.6
21.5.2
472
Backing
Dryer Conveyance Rollers
Dryer Exit Nip Roller
Winder Lay-on Roller
Static Control
474
474
474
System Maintenance
475
21.5.2.1
Clean Static Bars
476
21.5.2.2
Replace Ionizing String
476
21.5.2.3
Verify Gaps
Verify Performance
476
21.5.2.4
21.5.2.5
Clean
21.5.2.6
Restore Surfaces of
21.5.2.7
21.5.2.8
21.5.2.9
21.5.3
Roller
Rollers, Belts and Guides
476
Rollers
Tacky (Cleaning)
Check the Electrical Resistivity of Static
Dissipative Rollers
Test the Bearing Drag on Low Wrap Rollers
Align Roller
21.5.2.10
Nip
21.5.2.11
Lay-on
21.5.2.12
Web Tension
Pressure
Rollers
21.5.2.13
Winding
21.5.2.14
Tension Profile
Humidifier Maintenance
Conductive Layers in Products
References
Recommended
476
476
476
477
477
477
477
477
477
477
477
478
Reading
for Further Study
479