Handbook of Troubleshooting Plastics Processes: A Practical Guide -- Contents -- Preface -- List of Contributors -- Part 1: Troubleshooting Basics -- 1 The Economics of Troubleshooting Polymer Processing Systems -- 1.1 Introduction -- 1.2 Economic Incentives and Necessities -- 1.3 Troubleshooting Resources and Their Cost -- 1.4 Managing Resources and Costs -- 1.5 Troubleshooting Techniques and Their Relative Costs -- 1.6 Case Histories -- 1.6.1 Single Screw Extrusion Instability -- 1.6.2 Compounding Extruder Catastrophic Failure -- 1.6.3 Polymer Degradation During Melt Processing -- 1.7 Conclusions -- References -- 2 Troubleshooting Philosophy -- 2.1 Introduction -- 2.2 Troubleshooting Methodology -- Bibliography -- 3 Statistical Tools for Trouble Shooting a Process -- 3.1 Introduction -- 3.2 Basic Statistical Concepts -- 3.2.1 Histogram -- 3.2.2 Scatter Diagram -- 3.3 Sample Mean and Standard Deviation -- 3.4 Design of Experiments (DOE) -- 3.4.1 Factorial Design -- 3.4.2 Fractional Factorial Design -- 3.5 Process Capability -- 3.6 Control Charts -- 3.7.1 Central Limit Theorem -- 3.7.2 Variable Data Control Charts -- 3.7.3 Control Charts for Attribute Data -- References -- Bibliography -- Statistics -- Design of Experiments -- Statistical Process Control -- Part 2: Extrusion Processes -- 4 Single Screw Extrusion -- 4.1 Introduction -- 4.2 Process Description -- References -- 5 Troubleshooting the Co-rotating Fully Intermeshing Twin-screw Compounding System -- 5.1 Introduction -- 5.2 Equipment Description -- 5.3 Troubleshooting -- 5.3.1 What is Troubleshooting? -- 5.4 Tools of the Successful Troubleshooter -- 5.4.1 Experience -- 5.4.2 Vent Flow Problem -- 5.5 Product, Process and Equipment Knowledge -- 5.5.1 High Discharge Pressure Problem -- 5.5.2 Barrel Temperatures Higher than Set Points Problem -- 5.5.3 Climbing Discharge Temperature Problem.

5.5.4 Gels and Un-melts in the Extrudate Problem -- 5.5.5 Holes or Bubbles in the Extrudate Problem -- 5.5.6 Process Surging Problem -- 5.6 Conclusion -- References -- 6 Troubleshooting for Injection Molding -- 6.1 Introduction -- 6.1.1 The Basic Approach -- 6.2 Understanding Temperature Control -- 6.3 Product Shift to a Different Machine -- 6.3.1 Calculate the New Pressure Settings -- 6.3.2 Procedure -- 6.4 Part Weight as an Analytical Tool -- 6.4.1 Example - Part Weight for Process Variability Analysis -- 6.4.2 Long Term Variability Analysis -- 6.4.3 Short Term Variability Analysis -- 6.4.4 Variability Evaluation -- 6.4.5 Process Benchmarking for Quality -- 6.4.6 Benchmark Evaluation -- 6.4.7 Summary -- 6.5 Part Weight as Dimensional Aimpoint Control -- 6.5.1 Unconstrained Process -- 6.5.2 Partially Constrained Process -- 6.5.3 Constrained Process -- 6.5.4 Warpage -- 6.5.5 Relationship of Shot Weight and Hydraulic Pressure -- 6.6 Determining the Gate Freeze-Off Time -- 6.6.1 Procedure to Determine the Freeze-Off Point -- 6.6.2 Time Analysis -- 6.6.3 Pressure Procedure -- References -- 7 Blown Film -- 7.1 Introduction -- 7.2 Process Description -- 7.2.1 Extruders -- 7.2.2 Dies -- 7.2.3 Process Cooling -- 7.2.4 The Bubble Collapsing Process and Systems -- 7.2.5 Haul-Off/Primary Nip -- 7.2.6 Film Winding -- 7.2.6.1 Center-drive Winder -- 7.2.6.2 Surface Winders -- 7.3 Special Tools for Troubleshooting -- 7.3.1 Winding Systems -- 7.4 Case Studies -- 7.4.1 Case Study 1: Carbon Buildup -- 7.4.2 Case Study 2: Poor Gauge Uniformity -- References -- 8 Cast Film Troubleshooting -- 8.1 Coextrusion Film Systems -- 8.2 Troubleshooting Method -- 8.2.1 The Problem Statement -- 8.2.2 The Hypothesis -- 8.2.3 Testing the Hypothesis -- 8.2.4 Evaluating the Results -- 8.3 Common Problems, Hypotheses and Tests -- 8.3.1 Gels in Film -- 8.3.2 Film Clarity.

8.3.3 Wrinkling -- 8.3.4 Inability to Reach Output -- 8.3.5 Poor Melt Mixing -- 8.3.6 Melt Temperature Too Low -- 8.3.7 Melt Temperature Too High -- 8.3.8 Extruder Power Insufficient -- 8.3.9 Film Streaks or Lines -- 8.3.10 Melt Appearance Defects -- 8.3.11 Thickness Variation - Cross Direction -- 8.3.12 Thickness Variation - Machine Direction -- 8.3.13 Poor Wound Roll Appearance -- 8.3.14 Edge Tear (Unstable Edges) -- 8.3.15 Pin Holes -- 8.3.16 Extruder Surging -- 8.3.17 Draw Resonance -- 8.3.18 Film Discoloration -- 8.3.19 Poor Heat Seal Strength -- 8.3.20 Odor - Flavor Scalping -- 8.3.21 Poor Strength -- 8.3.22 Film Blocking -- 8.3.23 Poor Printability -- 8.3.24 Camber or Curl -- 8.3.25 Scratches -- References -- 9 Oriented Films-Troubleshooting and Characterization -- 9.1 Introduction -- 9.2 Process Overview: Biaxial Orientation -- 9.3 Oriented Film Markets -- 9.3.1 Oriented Polypropylene OPP or BOPP -- 9.3.2 Oriented Polyester OPET -- 9.3.3 Oriented Polystyrene OPS -- 9.3.4 Oriented Polyamide (Nylon) OPA -- 9.4 Troubleshooting the Film Orientation Process as Applied to OPP Films -- 9.4.1 Control Variables -- 9.4.1.1 Resin Drying -- 9.4.1.2 Extrusion -- 9.4.1.3 Casting and Pinning -- 9.4.1.4 Machine Direction Orientation -- 9.4.1.5 Transverse Direction Orientation -- 9.4.1.6 Web Handling and Surface Treatment -- 9.4.1.7 Winding -- 9.4.2 Noise Variables -- 9.4.3 Dependent Variables -- 9.5 Special Tools for Troubleshooting -- 9.6 Case Studies -- 9.6.1 Casting Capacity Limitation in PET Film Production -- 9.6.2 Floating Gauge - Extrusion Instability and MDO Heat Transfer Limitations -- 9.6.3 Output Limitation from Coextrusionlnstability -- References -- Bibliography -- 10 Troubleshooting the Thermoforming Process -- 10.1 General Concepts in Thermoforming -- 10.2 Categorization of the Process -- 10.2.1 Thick-Gauge Process -- 10.2.2 Thin-Gauge Process.

10.3 Specific Aspects of the Thermoforming Process -- 10.3.1 Critical Material Issues -- 10.3.2 Molds and Mold Design -- 10.3.3 Incoming Sheet Quality Issues -- 10.3.4 Materials Handling - Ingress -- 10.3.5 Heating -- 10.3.6 Pre-stretching (Plug Assist) -- 10.3.7 Pre-stretching (Vacuum/Air Pressure Formation) -- 10.3.8 Contacting the Mold -- 10.3.9 Cooling and Rigidifying the Formed Part -- 10.3.10 Removing the Formed Part from the Mold -- 10.3.11 Materials Handling - Egress -- 10.3.12 Trimming -- 10.3.13 Post-trimming Issues -- 10.3.14 Regrind -- 10.4 Problem Solving Methodology -- 10.4.1 Trimming -- 10.5 General Preventative Maintenance Concepts -- 10.5.1 Crisis Maintenance -- 10.5.2 Routine Maintenance -- 10.6 General Predictive Maintenance Concepts -- 10.7 Safety during Troubleshooting -- 10.7.1 Make-up of a Troubleshooting Team -- Appendix 1: 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 Proper Equipment Processing for Industrial/Technical Blow Molding -- 11.1 Introduction of Blow Molding -- 11.1.1 How Parts are Blow Molded -- 11.1.2 Positive Benefits of the Process -- 11.1.3 Negative Factors of Accumulator Head Blow Molding -- 11.2 Select the Proper Equipment -- 11.3 Extruder -- 11.4 Accumulator Head -- 11.5 Importance of Cleaning -- 11.6 Press -- 11.7 Hydraulics -- 11.8 Microprocessor -- 11.9 Pneumatic Systems -- 11.10 Part Take Out System -- 11.11 Selection of Equipment -- 12 PET Stretch Blow Molding -- 12.1 Introduction -- 12.2 The PET Universe -- 12.3 Technology History.

12.4 PET Chemistry -- 12.5 PET Morphology -- 12.6 Bottle Universe -- 12.7 Bottle Manufacturing -- 12.8 Commercial Manufacturing Processes -- 12.9 Process Elements -- 12.9.1 Injection Molding -- 12.9.1.1 IV Drop -- 12.9.1.2 Acetaldehyde -- 12.9.1.3 Molding Stresses -- 12.9.2 Hot Runner System -- 12.9.2.1 Gate Crystallinity and Separation -- 12.9.2.2 Gate Pin Holes -- 12.9.3 Mold Cooling -- 12.9.3.1 Preform Problem Analysis -- 12.9.4 Blow Molding -- 12.9.4.1 General Principles - Reheating and Preform Temperature -- 12.9.5 Preform Temperature Profiling -- 12.9.6 Blowing -- 12.9.6.1 Quality Attributes and Performance Issues -- 12.9.6.2 Blow Molding Process Monitoring -- 12.9.6.3 On Line Inspection -- 12.9.6.4 Testing and Test Procedures -- 12.9.6.5 Special Processes -- 12.10 Case Sample: Thermal Stability Failure of CSD Bottles -- References -- 13 Blow Molding - Problems and Solutions -- 13.1 Introduction -- 13.2 Troubleshooting -- 13.3 Variables Affecting the Blow Molding Process -- 13.3.1 PART I: Defects in Article -- 13.3.1.1 PART I - Defect in Finished Article -- 13.3.2 PART II: Parison Defects -- 13.3.2.1 PART II - Defects of the Parison -- 13.3.3 Noise -- 13.3.4 Ambient Conditions -- 13.4 Preventative Maintenance -- 13.4.1 Maintenance Recommendations -- 13.4.2 Machine Check Out -- 13.5 Injection and Stretch Blow Molding -- 13.6 Computer Integrated Manufacturing (CIM) in Extrusion Blow Molding -- Acknowledgement -- Bibliography -- 14 Extrusion Coating Troubleshooting -- 14.1 Coextrusion Extrusion Coating/Laminating Systems -- 14.2 Troubleshooting Method -- 14.3 Common Problems, Hypotheses and Tests -- 14.3.1 Gels in Film -- 14.3.2 Poor Adhesion -- 14.3.3 Wrinkling -- 14.3.4 Low Output -- 14.3.5 Poor Melt Mixing -- 14.3.6 Melt Temperature Too Low -- 14.3.7 Melt Temperature Too High -- 14.3.8 Extruder Power Insufficient -- 14.3.9 Die Lines.

14.3.10 Melt Appearance Defects.