Download Handbook of troubleshooting plastics processes : a practical guide
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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