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Handbook of Troubleshooting Plastics Processes

A Practical Guide
Edited by John R. Wagner, Jr
Series: Polymer Science and Plastics Engineering
Copyright: 2012   |   Status: Published
ISBN: 9780470639221  |  Hardcover  |  
502 pages | 216 illustrations
Price: $249 USD
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One Line Description
Provides a framework for understanding how to characterize plastic manufacturing processes for use in troubleshooting problems.

This troubleshooting handbook will provide a framework for process engineers, technical service and production personnel in all companies worldwide that manufacture plastics products and parts.

This handbook provides a framework for understanding how to characterize plastic manufacturing processes for use in troubleshooting problems. The technical level is for process engineers and production personnel. The 22 chapters are authored by well-known and experienced engineers who have specialized knowledge about the processes covered in this practical guide.

The book is divided into three parts: Part 1 introduces the philosophy of troubleshooting, the economics and management of troubleshooting, and outlines how to use statistics for process characterization and troubleshooting. Part 2 deals with plastics processes that use extrusion. Part 3 deals with plastics processes that do not use extruders and has a special chapter on static.

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Author / Editor Details
After gaining his BS and MS in chemical engineering from the University of Notre Dame in 1963 & 1965, John Wagner worked for BF Goodridge for 3 years and then in the Films Division at Mobil Chemical Company for 30 years. He is now a consultant in plastics products and processes. He has 23 patents to his name, is the editor of Journal of Plastic Film & Sheeting, as well as the editor or co-editor of 4 books on extrusion and packaging. John is a Fellow of the Society of Plastics Engineers and serves on the Extrusion Division and Flexible Plastics Packaging Division Boards.

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Table of Contents
Preface. List of Contributors. Part I: Troubleshooting Basics.
1 The Economics of Troubleshooting Polymer Processing Systems
Mark D. Wetzel

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
2 Troubleshooting Philosophy
John R. Wagner, Jr.

2.1 Introduction
2.2 Troubleshooting Methodology
3 Statistical Tools for Trouble Shooting a Process
Vincent Vezza

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
Design of Experiments
Statistical Process Control
Part II: Extrusion Processes
4 Single Screw Extrusion
John R. Wagner, Jr.

4.1 Introduction
4.2 Process Description
5 Troubleshooting the Co-rotating Fully Intermeshing Twin-screw Compounding System
Paul Andersen, Rich Kanarski and John R. Wagner, Jr.

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
6 Troubleshooting for Injection Molding
James J. Wenskus

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
7 Blown Film
Karen Xiao and Steve Gammell

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 Center-drive Winder 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
8 Cast Film Troubleshooting
Andrew W. Christie and Beth M. Foederer

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 Insuffi cient
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
9 Oriented Films - Trouble Shooting and Characterization
Eldridge M. Mount, III

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
Processas Applied to OPP Films
9.4.1 Control Variables Resin Drying Extrusion Casting and Pinning Machine Direction Orientation Transverse Direction Orientation Web Handling and Surface Treatment 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
9.6.3 Output Limitation from CoextrusionInstability
10 Troubleshooting the Thermoforming Process
James L. Throne

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 Specifi c 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
11 Proper Equipment Processing for Industrial/Technical Blow Molding
Robert A. Slawska

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
Dan Weissmann

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 IV Drop Acetaldehyde Molding stresses
12.9.2 Hot Runner System Gate Crystallinity and Separation Gate Pin Holes
12.9.3 Mold Cooling Preform Problem Analysis
12.9.4 Blow Molding General principles – Reheating and Preform Temperature
12.9.5 Preform Temperature Profiling
12.9.6 Blowing Quality Attributes and Performance Issues Blow Molding Process Monitoring On Line Inspection Testing and Test Procedures Special Processes
12.10 Case Sample: Thermal Stability Failure of CSD Bottles
13 Blow Molding – Problems and Solutions
Norman C. Lee

13.1 Introduction
13.2 Troubleshooting
13.3 Variables Affecting the Blow Molding Process
13.3.1 PART 1: Defects in Article PART I – Defect in Finished Article
13.3.2 PART II: Parison Defects 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 5
14 Extrusion Coating Troubleshooting
Beth M. Foederer and Andrew W. Christie

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
14.3.11 Thickness Variation – Cross Direction
14.3.12 Thickness Variation – Machine Direction
14.3.13 Poor Wound Roll Appearance
14.3.14 Edge Tear (Unstable Edges)
14.3.15 Pin Holes
14.3.16 Extruder Surging
14.3.17 Draw Resonance
14.3.18 Poor Heatseal
14.3.19 Odor – Flavor Scalping
14.3.20 Poor Printability
14.3.21 Camber or Curl
14.3.22 Scratches
Part III: Non-extrusion Processes
15 Adhesive and Thermal Lamination
Tom Dunn

15.1 Introduction
15.1.1 Process Overview
15.1.2 Markets Served
15.1.3 Historical and Future Growth Projections – Technology
Challenges and Threats
15.2 Process Description
15.2.1 Major Process Components
15.2.2 Equipment Production Ranges
15.2.3 Manufacturers
15.3 Control Variables
15.4 Random Cause Variables
15.5 Dependent Variables
15.6 Special Tools for Troubleshooting
15.6.1 Product
15.7 Case Studies
15.7.1 Easy-peel or Rip-off
15.7.2 Spotty Results
16 Troubleshooting for Rotomolding
Paul Nugent

16.1 The Basic Process
16.2 Key Quality Control Steps in Rotomolding
16.2.1 Materials In-bound and Powder Preparation
16.2.2 Colorants and Additives
16.2.3 Material Mixing
16.2.4 Molds and Fixtures
16.2.5 Machinery
16.2.6 Calibration
16.2.7 Production Process and Records
16.3 Typical Rotomolding Problems
16.4 Typical Solutions
16.4.1 Adhesion – Diffi culty in Painting or Applying Labels
16.4.2 Blowholes – Around Inserts
16.4.3 Blowholes – Other Areas
16.4.4 Blowholes – Parting Line
16.4.5 Bubbles on Part Surface or in the Cross-section
16.4.6 Coining (Pockmarks)
16.4.7 Color – Part Burned/Discolored
16.4.8 Color – Static Swirl
16.4.9 Color – Unevenness
16.4.10 Flash at the Parting Line
16.4.11 Foaming – Coarse or Uneven Foam
16.4.12 Foaming – Gaps in Wall Cross-section
16.4.13 Foaming – Part Deformation
16.4.14 Incomplete Material Fusion
16.4.15 Incomplete Mold Fill (Bridging)
16.4.16 Low Impact Strength
16.4.17 Low Part Stiffness
16.4.18 Long Oven Cycle
16.4.19 Long-term Part Failure
16.4.20 Mold Distortion, Explosion
16.4.21 Plate Out
16.4.22 Sticking in Mold
16.4.23 Wall Thickness – Uneven
16.4.24 Warpage
16.4.25 Whitish Part Appearance
17 Plastics Calendering
Chellappa Chandrasekaran

17.1 Introduction
17.2 Blending and Fluxing
17.3 Mills and Strainers
17.4 Calender
17.5 General Description of a Calendering Machine
17.5.1 Rolls
17.5.2 Sheet Finishes
17.5.3 Roll Contours
17.5.4 Frame
17.5.5 Roll Adjustment
17.5.6 Bed Plate
17.5.7 Lubrication
17.5.8 Temperature Control
17.5.9 Safety and Safety Regulations
17.6 The Calendering Process
17.6.1 Heating and Delivery to the Calender
17.6.2 Roll Banks
17.6.3 Sheet Takeoff and Post-processing
17.6.4 Embossing and Laminating
17.7 Input Materials and Products
17.7.1 The Formulas
17.8 Why Calendering is Preferred to Extrusion
17.9 Calendering Process Variables
17.9.1 Barring and Noise Due to Roll Vibration
17.9.2 Machine Dependent Variable
17.9.3 Product Variation
17.9.4 Overcoming and Correcting Process Variation
17.10 Conclusion
18 Compression Molding
Muralisrinivasan Natamai Subramanian

18.1 Introduction
18.2 Materials
18.2.1 Thermoplastics and Compression Molding
18.2.2 Thermosets and Compression Molding
18.2.3 Premix or Prepreg Preparation
18.2.4 Fiber Alignment
18.2.5 Pre-form
18.2.6 Prepreg
18.3 Sheet Molding Compound – Production
18.3.1 Mold
18.4 Technology – Compression Molding
18.4.1 Important Variables during Processing
18.5 Troubleshooting
18.6 Problems and Solution(s)
18.7 Summary
18.7.1 Fundamentals
18.7.2 Advantages
18.7.3 Disadvantages
18.7.4 Future Trends
19 Transfer Molding
Muralisrinivasan Natamai Subramanian

19.1 Introduction
19.2 Curing
19.3 Processing
19.4 Mold
19.5 Process Optimization
19.6 Method
19.7 Pot Type Transfer Molding
19.7.1 Plunger/Transfer Molding
19.7.2 Screw Type Transfer Molding
19.7.3 Screw Injection Type
19.8 Troubleshooting
19.9 Summary
19.9.1 Advantages
19.9.2 Disadvantages
19.9.3 Future Trends
19.9.4 Fundamentals
20 Pultrusion Process Troubleshooting
Joseph E. Sumerak

20.1 Introduction
20.1.1 Pultruded Products are Governed by a Performance Specification
20.2 Materials Review
20.2.1 Resin
12.2.2 Resin Reactivity
20.2.3 Resin Reactivity Measurement
20.2.4 Resin Viscosity
20.2.5 Reinforcements
20.3 Process Parameters
20.3.1 Composition and Process Specification
20.4 Manufacturing Defects
20.4.1 Defects
20.5 Material Related Defects
20.5.1 Resin
20.5.2 Reinforcements
20.6 Process Parameter Related Defects
20.7 Methods Related Defects
20.8 The Troubleshooting Process
20.8.1 Subjective versus Objective
20.8.2 Visual Tools
20.8.3 On-Line Quantitative Analysis Tools
20.8.4 Off-Line Quality Assessment Tools
20.9 Troubleshooting Examples
20.10 Summary
21 Troubleshooting Static Problems in Plastics Processes
Kelly Robinson

21.1 Introduction
21.1.1 Nature and Character of Static
21.1.2 Cost of Static Problems
21.2 Root Causes of Static
21.2.1 Tribocharging/Contact Charging Triboelectric Series
21.2.2 Application of the Triboelectric Series
21.2.3 Charge Induction
21.2.4 Ionizer Imbalance (Active Charging)
21.3 Static Measurement Tools
21.3.1 Electrostatic Fieldmeters (FMs) and Non-Contacting Electrostatic
Voltmeters (ESVMs) Electrostatic Fieldmeters – Fieldmeters Respond to
Net Charge Non-contacting Electrostatic Voltmeter – Voltmeters
Respond to Surface Charge Spatial Resolution and Response Time Typical Applications – Monitor Static Performance with
Fieldmeters and Voltmeters
21.3.2 Charge Meter – Coulomb Meters are a Direct Measure of Charge Principles of Operation Typical Applications
21.3.3 Resistivity Meters Volumetric Resistivity Meters Surface Resistivity Meters
21.3.4 Charge Dissipation Time Measurements Importance of Charge Dissipation Time Principles of Operation – Static Dissipation Time Typical Application – Static Dissipation Time
21.4 Static Problem Diagnosis
21.4.1 Understand the Problem
21.4.2 Baseline Data and Control Charts
21.4.3 Hot Rolls
21.4.4 Static Specifications
21.5 Solving Static Problems
21.5.1 Locate the Source of Charge Separation Unwinding Roll Drive Roller Coater Backing Roller Dryer Conveyance Rollers Dryer Exit Nip Roller Winder Lay-on Roller
21.5.2 Static Control System Maintenance Clean Static Bars Replace Ionizing String Verify Gaps Verify Performance Clean Rollers, Belts and Guides Restore Surfaces of Tacky (Cleaning) Rollers Check the Electrical Resistivity of Static
Dissipative Rollers Test the Bearing Drag on Low Wrap Rollers Align Roller Nip Pressure Lay-on Rollers Web Tension Winding Tension Profile Humidifier Maintenance
21.5.3 Conductive Layers in Products
Recommended reading for further study

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TEC055000: Technology & Engineering/Textiles & Polymers
TEC009060: Technology & Engineering/Industrial Engineering
TEC021000: Technology & Engineering/Materials Science
TDCP: Plastics & Polymers Technology
KND: Manufacturing Industries
TGM: Materials Science

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