Injection Molding Handbook Herausgegeben von Tim A. Osswald, Lih-Sheng Turng, Paul Gramann

Transcription

1 Injection Molding Handbook Herausgegeben von Tim A. Osswald, Lih-Sheng Turng, Paul Gramann ISBN-10: ISBN-13: Inhaltsverzeichnis Weitere Informationen oder Bestellungen unter sowie im Buchhandel

2 Contents Preface vii Contributors xix 1 Introduction P. J. Gramann, T. A. Osswald 1.1 Historical Background The Reciprocating Screw Injection Molding Machine The Plasticating and Injection Unit The Clamping Unit The Mold Cavity The Injection Molding Cycle Related Injection Molding Processes References Injection Molding Materials T. A. Osswald 2.1 Historical Background Macromolecular Structure of Polymers Molecular Weight Conformation and Configuration of Polymer Molecules Thermoplastic Polymers Amorphous Thermoplastics Semi-Crystalline Thermoplastics Examples of Common Thermoplastics Thermosetting Polymers Cross-Linking Reaction Examples of Common Thermosets Copolymers and Polymer Blends Elastomers M. DeGreiff 2.9 Efficient Vulcanizing Systems Thermoplastic Elastomers G. Holden Service Temperatures Examples of Common Thermoplastic Elastomers References

3 x Contents 3 Processing Fundamentals T. A. Osswald 3.1 Processing Data Temperature Settings Injection and Pack-Hold Pressure Settings Drying Processing Data for Thermoplastic Elastomers G. Holden Processing Data for Thermosets Processing Data for Elastomers Rheology of Polymer Melts Shear Thinning Behavior of Polymers Simplified Flows Common in Injection Molding Estimating Injection Pressure and Clamping Force (Stevenson Model) Nonisothermal Flows in Polymer Processing Normal Stresses in Shear Flow Deborah Number Rheology of Curing Thermosets Suspension Rheology Rheometry The Melt Flow Indexer The Capillary Viscometer Viscosity from the Capillary Viscometer Anisotropy Development During Processing Orientation in the Final Part Fiber Damage Solidification and Curing Processes Solidification of Thermoplastics Solidification of Thermosets Residual Stresses, Shrinkage, and Warpage References Plasticating C. Rauwendaal, P. J. Gramann 4.1 The Plasticating Unit The Ram Extruder The Reciprocating Screw Functions of the Plasticating Unit Solids Conveying Melting or Plasticating Melt Conveying Degassing or Devolatilization Mixing Conclusion References

4 Contents xi 5 Clamping Unit R. Farrell 5.1 Metal Fatigue and Its Importance in Clamp Design Importance in Clamp Design A Brief History of Metal Fatigue The Three Phases of Metal Fatigue Determination of Design Stress for Metal Fatigue Determination of Survival Factor (SF) Conclusion of Discussion of Metal Fatigue Functions of the Clamping System The Three Types of Clamping Systems Hydraulic Hydromechanical Mechanical Types of Toggle Systems Key Elements of a Clamp Platens Tie Rods and Nuts Toggle Pins and Bushings Tie-Rod Bushings Moving Platen Support Shut Height Adjustment Ejector Systems A Special Discussion of Tie-Rod Design Why This Element Is So Important Thread Load Distribution Thread Bending Stress Thread Axial Stress Combined Stresses Mitigating Factors Ways to Improve the Design Understanding Clamp Spring Rate (Stiffness) How to Determine Clamp Spring Rate The Importance of Clamp Spring Rate Math Model for a Toggle Clamp The Farrell Square Root Rule Relationships That Follow from the Farrell Square Root Rule The Whole Machine Can Follow the Square Root Rule References Mold Design J. Beaumont 6.1 Standard Mold Assembly Cold Runner Molds Two-Plate Cold Runner Mold Three-Plate Cold Runner Mold Hot Runner Molds Externally Heated Manifold and Drops

5 xii Contents Externally Heated Manifold with Internally Heated Drops Internally Heated Manifold and Internally Heated Drops Insulated Manifold and Drops Miscellaneous Hot Runner Systems Design Hot Sprues Hot Drops (Nozzles) Special Considerations in the Operation of Hot Runner Molds Stack Molds Runner Design Cold Runner Design Runner Balancing in Geometrically Balanced Runners (Cold and Hot Runners) Nongeometrically Balanced Runner Layouts Gate Design Gate Types Positioning Gates Structural Design of a Mold for Long Life and Rigidity Mold Material Selection Fatigue Deflection of Side Walls Core Deflection Deflection of Support Plates Mold Cooling Practical Considerations Thermal Expansion Parallel versus Series Cooling Circuits Baffles and Bubblers Mold Ejection Systems Basic Ejection Problems Means of Ejection Ejection Considerations Ejection Design Vent Design References Material Handling and Auxiliary Equipment S. Collins 7.1 Bulk Material Handling Pneumatic Conveying Systems Receivers and Loaders Self-Contained Loaders Material Handling Controls Feeders and Blenders Dryers Inntegrated Drying and Conditioning System Mold and Process Temperature Control Automation Granulators

6 Contents xiii 8 Statistical Process Control C. Rauwendaal 8.1 Statistical Process Control Implementing Statistical Process Control Basic Statistical Concepts Control Charts Introduction Control Charts for Variables Data Control Charts for Attributes Data Process Capability and Special SPC Tools for Molding Introduction Capability Indexes Use of Computers Special SPC Techniques for Injection Molding References Special Injection Molding Processes L.-S. Turng 9.1 Coinjection (Sandwich) Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Fusible (Lost, Soluble) Core Injection Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Gas-Assisted Injection Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Injection-Compression Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Computer Simulation for Injection-Compression Molding In-Mold Decoration and In-Mold Lamination Process Description Process Advantages Process Disadvantages Mold Design and Processing Considerations

7 xiv Contents Applicable Materials Typical Applications Insert and Outsert Molding Insert Molding Process Description Outsert Molding Process Description Lamellar (Microlayer) Injection Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Low-Pressure Injection Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Microinjection Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Microcellular Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Multicomponent Injection Molding (Overmolding) Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Multiple Live-Feed Injection Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Push-Pull Injection Molding Process Description Process Advantages and Disadvantages Applicable Materials Typical Applications Powder Injection Molding Process Description Process Advantages

8 Contents xv Process Disadvantages Typical Applications Reaction Injection Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Resin Transfer Molding and Structural RIM Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Rheomolding Process Description Process Advantages Process Disadvantages Structural Foam Injection Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Thin-Wall Molding Process Description Process Advantages Process Disadvantages Applicable Materials Typical Applications Vibration Gas Injection Molding Process Description Water Assisted Injection Molding Process Description Process Advantages Process Disadvantages Applicable Materials Rubber Injection M. DeGreiff, N. Castaño Rubber Molding Processes Curing Systems in Rubber Injection Process Injection Molding of Liquid Silicone Rubber Acknowledgement References

9 xvi Contents 10 Part Design J. Beaumont 10.1 The Design Process The Four Building Blocks of Plastics Part Design Material Product Design Mold Design and Machining Process Part Design Guidelines for Injection Molded Plastic Parts Designing the Primary Wall Ribs, Gussets, and Bosses Bosses Corners, Fillets, and Radii Taper and Draft Angles Undercuts and Holes Gating and Process Considerations Cores Avoid Picture Frame Features Integral Hinges Sample Part Design Estimating Part Costs References Simulation in Injection Molding B. A. Davis, A. C. Rios, V. Yang 11.1 Introduction History Governing Equations Flow Models Orientation Models Heat Transfer Models Constitutive Equations Numerical Methods Finite Difference Method Finite Element Method Boundary Element Method Finite Volume Method Simplified Calculations Finite Difference Based Calculations Midplane Model-Based Calculations Solid Model-Based Calculations True 3-D Claculations Advanced Calculations Commercial Software Specialty Calculations Injection-Compression Molding IC Molding of Thermoplastic Materials IC Molding of Thermoset Materials

10 Contents xvii 11.8 Molding Process Optimization Optimal Gating Active Process Control Conclusions Acknowledgements References Process Troubleshooting Introduction to Troubleshooting J. Wickman, T. Springett, and R. Vadlamudi 12.2 Troubleshooting Guide Troubleshooting Table J. Bozzelli Troubleshooting on Injection Molding of Rubber M. DeGreiff Important Troubleshooting Considerations T. Osswald 12.3 Technology and Process Troubleshooting J. Wickman, T. Springett, and R. Vadlamudi Technology Implications Injection Molding Process and Sensors Pressure Sensors Temperature Sensors Process Monitoring Automatic Troubleshooting Design of Experiments Factorial Design of Experiments Conclusions J. Wickman, T. Springett, and R. Vadlamudi References Materials Troubleshooting M. Sepe 13.1 Composition Problems Diagnostic Tools for the Polymer Diagnostic Tools for Fillers and Reinforcements Diagnostic Tools for Additives Molecular Weight Problems Performance Problems Material Selection Process Use of Fillers Deflection Temperature Under Load Impact Properties A Brief Discussion of Viscoelasticity Conclusion References Index