Handbook of Troubleshooting Plastics Processes: A Practical Guide

Handbook of Troubleshooting Plastics Processes: A Practical Guide......Page 5
Contents......Page 7
Preface......Page 19
List of Contributors......Page 21
Part 1: Troubleshooting Basics......Page 25
1.1 Introduction......Page 27
1.2 Economic Incentives and Necessities......Page 28
1.3 Troubleshooting Resources and Their Cost......Page 30
1.4 Managing Resources and Costs......Page 35
1.5 Troubleshooting Techniques and Their Relative Costs......Page 36
1.6.2 Compounding Extruder Catastrophic Failure......Page 38
1.6.3 Polymer Degradation During Melt Processing......Page 40
References......Page 44
2.1 Introduction......Page 45
2.2 Troubleshooting Methodology......Page 47
Bibliography......Page 49
3.1 Introduction......Page 51
3.2.2 Scatter Diagram......Page 52
3.3 Sample Mean and Standard Deviation......Page 53
3.4.1 Factorial Design......Page 55
3.4.2 Fractional Factorial Design......Page 59
3.5 Process Capability......Page 62
3.6 Control Charts......Page 63
3.7.2 Variable Data Control Charts......Page 65
3.7.3 Control Charts for Attribute Data......Page 68
Statistics......Page 69
Statistical Process Control......Page 70
Part 2: Extrusion Processes......Page 71
4.1 Introduction......Page 73
4.2 Process Description......Page 75
References......Page 78
5.1 Introduction......Page 81
5.2 Equipment Description......Page 82
5.3 Troubleshooting......Page 83
5.4.1 Experience......Page 84
5.4.2 Vent Flow Problem......Page 85
5.5 Product, Process and Equipment Knowledge......Page 86
5.5.1 High Discharge Pressure Problem......Page 88
5.5.5 Holes or Bubbles in the Extrudate Problem......Page 89
5.6 Conclusion......Page 90
References......Page 91
6.1 Introduction......Page 93
6.2 Understanding Temperature Control......Page 94
6.3.1 Calculate the New Pressure Settings......Page 96
6.3.2 Procedure......Page 97
6.4 Part Weight as an Analytical Tool......Page 98
6.4.1 Example – Part Weight for Process Variability Analysis......Page 99
6.4.4 Variability Evaluation......Page 100
6.4.5 Process Benchmarking for Quality......Page 101
6.4.6 Benchmark Evaluation......Page 102
6.5 Part Weight as Dimensional Aimpoint Control......Page 103
6.5.1 Unconstrained Process......Page 104
6.5.2 Partially Constrained Process......Page 105
6.5.4 Warpage......Page 106
6.5.5 Relationship of Shot Weight and Hydraulic Pressure......Page 108
6.6 Determining the Gate Freeze-Off Time......Page 109
6.6.3 Pressure Procedure......Page 110
References......Page 112
7.1 Introduction......Page 113
7.2 Process Description......Page 116
7.2.2 Dies......Page 118
7.2.3 Process Cooling......Page 121
7.2.4 The Bubble Collapsing Process and Systems......Page 122
7.2.5 Haul-Off/Primary Nip......Page 123
7.2.6 Film Winding......Page 125
7.2.6.2 Surface Winders......Page 126
7.3 Special Tools for Troubleshooting......Page 129
7.3.1 Winding Systems......Page 132
7.4.1 Case Study 1: Carbon Buildup......Page 133
7.4.2 Case Study 2: Poor Gauge Uniformity......Page 134
References......Page 135
8.1 Coextrusion Film Systems......Page 137
8.2 Troubleshooting Method......Page 138
8.2.2 The Hypothesis......Page 139
8.2.3 Testing the Hypothesis......Page 140
8.3.1 Gels in Film......Page 141
8.3.3 Wrinkling......Page 144
8.3.4 Inability to Reach Output......Page 145
8.3.5 Poor Melt Mixing......Page 146
8.3.7 Melt Temperature Too High......Page 147
8.3.9 Film Streaks or Lines......Page 148
8.3.11 Thickness Variation – Cross Direction......Page 149
8.3.13 Poor Wound Roll Appearance......Page 150
8.3.15 Pin Holes......Page 151
8.3.17 Draw Resonance......Page 152
8.3.21 Poor Strength......Page 153
8.3.23 Poor Printability......Page 154
References......Page 155
9.1 Introduction......Page 157
9.2 Process Overview: Biaxial Orientation......Page 158
9.3.1 Oriented Polypropylene OPP or BOPP......Page 165
9.3.2 Oriented Polyester OPET......Page 167
9.3.3 Oriented Polystyrene OPS......Page 168
9.3.4 Oriented Polyamide (Nylon) OPA......Page 169
9.4.1.1 Resin Drying......Page 170
9.4.1.2 Extrusion......Page 171
9.4.1.3 Casting and Pinning......Page 173
9.4.1.4 Machine Direction Orientation......Page 177
9.4.1.5 Transverse Direction Orientation......Page 179
9.4.1.7 Winding......Page 180
9.4.3 Dependent Variables......Page 181
9.5 Special Tools for Troubleshooting......Page 182
9.6.1 Casting Capacity Limitation in PET Film Production......Page 183
9.6.2 Floating Gauge – Extrusion Instability and MDO Heat Transfer Limitations......Page 184
9.6.3 Output Limitation from Coextrusionlnstability......Page 186
Bibliography......Page 188
10.1 General Concepts in Thermoforming......Page 191
10.2.1 Thick-Gauge Process......Page 193
10.2.2 Thin-Gauge Process......Page 194
10.3.1 Critical Material Issues......Page 196
10.3.2 Molds and Mold Design......Page 197
10.3.4 Materials Handling – Ingress......Page 198
10.3.5 Heating......Page 199
10.3.8 Contacting the Mold......Page 200
10.3.9 Cooling and Rigidifying the Formed Part......Page 201
10.3.12 Trimming......Page 202
10.3.13 Post-trimming Issues......Page 203
10.4 Problem Solving Methodology......Page 204
10.4.1 Trimming......Page 206
10.5 General Preventative Maintenance Concepts......Page 207
10.5.2 Routine Maintenance......Page 208
10.6 General Predictive Maintenance Concepts......Page 211
10.7 Safety during Troubleshooting......Page 212
10.7.1 Make-up of a Troubleshooting Team......Page 216
Appendix 2: Plastic Materials References......Page 217
Appendix 3: Troubleshooting Guidelines for Thick-Gauge Thermoforming......Page 218
Appendix 4: Troubleshooting Guidelines for Thin-Gauge Thermoforming......Page 223
Appendix 5: Time-dependent Ranking of Typical Courses of Action......Page 233
Thin-Gauge......Page 234
Thick-Gauge......Page 237
11 Proper Equipment Processing for Industrial/Technical Blow Molding......Page 241
11.1.1 How Parts are Blow Molded......Page 242
11.1.3 Negative Factors of Accumulator Head Blow Molding......Page 243
11.2 Select the Proper Equipment......Page 244
11.3 Extruder......Page 246
11.4 Accumulator Head......Page 249
11.5 Importance of Cleaning......Page 250
11.6 Press......Page 253
11.7 Hydraulics......Page 254
11.8 Microprocessor......Page 256
11.10 Part Take Out System......Page 257
11.11 Selection of Equipment......Page 258
12.1 Introduction......Page 261
12.2 The PET Universe......Page 262
12.4 PET Chemistry......Page 263
12.5 PET Morphology......Page 265
12.6 Bottle Universe......Page 267
12.7 Bottle Manufacturing......Page 269
12.8 Commercial Manufacturing Processes......Page 271
12.9.1.1 IV Drop......Page 275
12.9.1.2 Acetaldehyde......Page 278
12.9.1.3 Molding Stresses......Page 280
12.9.2 Hot Runner System......Page 282
12.9.2.1 Gate Crystallinity and Separation......Page 283
12.9.3 Mold Cooling......Page 284
12.9.4.1 General Principles – Reheating and Preform Temperature......Page 285
12.9.5 Preform Temperature Profiling......Page 287
12.9.6 Blowing......Page 288
12.9.6.1 Quality Attributes and Performance Issues......Page 290
12.9.6.2 Blow Molding Process Monitoring......Page 293
12.9.6.4 Testing and Test Procedures......Page 295
12.9.6.5 Special Processes......Page 296
12.10 Case Sample: Thermal Stability Failure of CSD Bottles......Page 301
References......Page 302
13.1 Introduction......Page 305
13.3.1 PART I: Defects in Article......Page 307
13.3.1.1 PART I – Defect in Finished Article......Page 308
13.3.2 PART II: Parison Defects......Page 313
13.3.2.1 PART II – Defects of the Parison......Page 314
13.4.1 Maintenance Recommendations......Page 317
13.5 Injection and Stretch Blow Molding......Page 318
13.6 Computer Integrated Manufacturing (CIM) in Extrusion Blow Molding......Page 320
Bibliography......Page 322
14.1 Coextrusion Extrusion Coating/Laminating Systems......Page 323
14.2 Troubleshooting Method......Page 324
14.3.1 Gels in Film......Page 325
14.3.2 Poor Adhesion......Page 328
14.3.3 Wrinkling......Page 329
14.3.4 Low Output......Page 330
14.3.5 Poor Melt Mixing......Page 331
14.3.7 Melt Temperature Too High......Page 332
14.3.10 Melt Appearance Defects......Page 333
14.3.12 Thickness Variation – Machine Direction......Page 334
14.3.14 Edge Tear (Unstable Edges)......Page 335
14.3.17 Draw Resonance......Page 336
14.3.20 Poor Printability......Page 337
References......Page 338
Part 3: Non-extrusion Processes......Page 339
15.1.1 Process Overview......Page 341
15.1.3 Historical and Future Growth Projections – Technology Challenges and Threats......Page 342
15.2.3 Manufacturers......Page 343
15.3 Control Variables......Page 344
15.4 Random Cause Variables......Page 348
15.5 Dependent Variables......Page 349
15.6 Special Tools for Troubleshooting......Page 350
15.6.1 Product......Page 351
15.7.1 Easy-peel or Rip-off......Page 352
Bibliography......Page 354
16.1 The Basic Process......Page 355
16.2 Key Quality Control Steps in Rotomolding......Page 360
16.2.1 Materials In-bound and Powder Preparation......Page 361
16.2.4 Molds and Fixtures......Page 363
16.2.7 Production Process and Records......Page 364
16.3 Typical Rotomolding Problems......Page 367
16.4.2 Blowholes – Around Inserts......Page 371
16.4.4 Blowholes – Parting Line......Page 372
16.4.5 Bubbles on Part Surface or in the Cross-section......Page 373
16.4.7 Color – Part Burned /Discolored......Page 374
16.4.8 Color – Static Swirl......Page 375
16.4.10 Flash at the Parting Line......Page 376
16.4.12 Foaming – Gaps in Wall Cross-section......Page 377
16.4.14 Incomplete Material Fusion......Page 378
16.4.16 Low Impact Strength......Page 379
16.4.17 Low Part Stiffness......Page 380
16.4.19 Long-term Part Failure......Page 381
16.4.21 Plate Out......Page 382
16.4.22 Sticking in Mold......Page 383
16.4.24 Warpage......Page 384
16.4.25 Whitish Part Appearance......Page 385
17.1 Introduction......Page 387
17.2 Blending and Fluxing......Page 388
17.4 Calender......Page 389
17.5.1 Rolls......Page 391
17.5.2 Sheet Finishes......Page 392
17.5.3 Roll Contours......Page 393
17.5.6 Bed Plate......Page 394
17.5.8 Temperature Control......Page 395
17.6 The Calendering Process......Page 396
17.6.2 Roll Banks......Page 397
17.6.4 Embossing and Laminating......Page 398
17.7.1 The Formulas......Page 399
17.9.1 Barring and Noise Due to Roll Vibration......Page 401
17.9.2 Machine Dependent Variable......Page 402
17.9.3 Product Variation......Page 403
17.10 Conclusion......Page 405
Bibliography......Page 406
18.1 Introduction......Page 407
18.2.1 Thermoplastics and Compression Molding......Page 408
18.2.2 Thermosets and Compression Molding......Page 409
18.3 Sheet Molding Compound – Production......Page 410
18.4 Technology – Compression Molding......Page 412
18.4.1 Important Variables during Processing......Page 413
18.5 Troubleshooting......Page 414
18.6 Problems and Solution(s)......Page 416
18.7.2 Advantages......Page 417
18.7.4 Future Trends......Page 418
References......Page 419
19.1 Introduction......Page 421
19.2 Curing......Page 422
19.3 Processing......Page 423
19.5 Process Optimization......Page 424
19.7 Pot Type Transfer Molding......Page 425
19.7.3 Screw Injection Type......Page 426
19.8 Troubleshooting......Page 427
19.9.2 Disadvantages......Page 428
References......Page 429
20.1 Introduction......Page 431
20.1.1 Pultruded Products are Governed by a Performance Specification......Page 433
20.2.1 Resin......Page 434
20.2.2 Resin Reactivity......Page 435
20.2.3 Resin Reactivity Measurement......Page 436
20.2.4 Resin Viscosity......Page 438
20.2.5 Reinforcements......Page 439
20.3 Process Parameters......Page 440
20.4.1 Defects......Page 441
20.5.1 Resin......Page 443
20.5.2 Reinforcements......Page 444
20.6 Process Parameter Related Defects......Page 446
20.7 Methods Related Defects......Page 450
20.8.1 Subjective versus Objective......Page 453
20.8.2 Visual Tools......Page 454
20.8.3 On-Line Quantitative Analysis Tools......Page 458
20.8.4 Off-Line Quality Assessment Tools......Page 459
20.10 Summary......Page 462
References......Page 463
21.1.1 Nature and Character of Static......Page 465
21.1.2 Cost of Static Problems......Page 466
21.2.1 Tribocharging/Contact Charging......Page 467
21.2.1.1 Triboelectric Series......Page 468
21.2.2 Application of the Triboelectric Series......Page 469
21.2.4 Ionizer Imbalance (Active Charging)......Page 470
21.3.1.1 Electrostatic Fieldmeters – Fieldmeters Respond to Net Charge......Page 471
21.3.1.2 Non-contacting Electrostatic Voltmeter – Voltmeters Respond to Surface Charge......Page 472
21.3.1.3 Spatial Resolution and Response Time......Page 474
21.3.1.4 Typical Applications – Monitor Static Performance with Fieldmeters and Voltmeters......Page 475
21.3.2.1 Principles of Operation......Page 479
21.3.2.2 Typical Applications......Page 480
21.3.3.1 Volumetric Resistivity Meters......Page 481
21.3.3.2 Surface Resistivity Meters......Page 484
21.3.4.2 Principles of Operation – Static Dissipation Time......Page 487
21.4.1 Understand the Problem......Page 488
21.4.2 Baseline Data and Control Charts......Page 489
21.4.3 Hot Rolls......Page 491
21.4.4 Static Specifications......Page 493
21.5 Solving Static Problems......Page 494
21.5.1.1 Unwinding Roll......Page 495
21.5.1.3 Coater Backing Roller......Page 496
21.5.1.6 Winder Lay-on Roller......Page 498
21.5.2 Static Control System Maintenance......Page 499
21.5.2.7 Check the Electrical Resistivity of Static Dissipative Rollers......Page 500
21.5.3 Conductive Layers in Products......Page 501
References......Page 502
Recommended Reading for Further Study......Page 503