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Handbook of Molded Part Shrinkage and Warpage
- 2nd Edition - December 26, 2012
- Author: Jerry Fischer
- Language: English
- Hardback ISBN:9 7 8 - 1 - 4 5 5 7 - 2 5 9 7 - 7
- eBook ISBN:9 7 8 - 1 - 4 5 5 7 - 3 0 5 7 - 5
How easy life would be if only moldings were the same size and shape as the mold. But they never are, as molders, toolmakers, designers and end users know only too well. Shrinkage… Read more
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Request a sales quoteHow easy life would be if only moldings were the same size and shape as the mold. But they never are, as molders, toolmakers, designers and end users know only too well. Shrinkage means that the size is always different; warpage often changes the shape too. The effects are worse for some plastics than others. Why is that? What can you do about it? The Handbook of Molded Part Shrinkage and Warpage is the first and only book to deal specifically with this fundamental problem. Jerry Fischer’s Handbook explains in plain terms why moldings shrink and warp, shows how additives and reinforcements change the picture, sets out the effect of molding process conditions, and explains why you never can have a single ‘correct’ shrinkage value. It goes on to demonstrate how to alleviate the problem through careful design of the molded part and the mold, and by proper material selection. It also examines computer-aided methods of forecasting shrinkage and warpage. And most important of all, the Handbook gives you the data you need to work with.
- Authoritative and rooted in extensive industrial experience, the expert guidance contained in this handbook offers practical understanding to novices, and new insights to readers already skilled in the art of injection molding and mold making
- Contains the answers to common problems and detailed advice on how to control mold and post-mold shrinkage and warpage
- Case Studies illustrate and enrich the text; Data tables provide the empirical data that is essential for success, but hard to come by
Engineers, scientists and technicians specializing in injection molding of plastic components. Designers of plastic components. Process and product manufacturing control engineers. Product development engineers
PDL Handbook Series
Preface
Acknowledgments
1. Introduction to Injection Molding
1.1 Introduction to Plastics
1.2 Interactivity Basics
1.3 Thermal Principles Governing Injection Molding
References
2. Shrinkage and Warpage
2.1 In-Mold Shrinkage
2.2 Warpage
2.3 Postmold Shrinkage
References
3. Causes of Molded-Part Variation: Part Design
3.1 Wall Thickness
3.2 Ribs
3.3 Bosses
3.4 Example of Proper Part Design
3.5 Other Design Considerations
References
4. Causes of Molded-Part Variation: Material
4.1 Amorphous and Semicrystalline Resins
4.2 Effects of Fillers, Reinforcements, Pigments, Time, and Stress
4.3 Shrinkage Predictions: Using PVT Relationships
References
5. Causes of Molded-Part Variation: Mold Design
5.1 Cavity Dimensions and Design Factors
5.2 Gate Types
5.3 Gate Location
5.4 Gate Size
5.5 Gate Design Systems
5.6 Runner Design
5.7 Mold Cooling Design
5.8 Mold Construction Materials
5.9 Prototype Molding with Stereolithography or Similar Type Molds
5.10 Pitfalls to Avoid
References
6. Causes of Molded Part Variation: Processing
6.1 Molding Conditions
6.2 Injection Melt Temperature
6.3 Injection Rate and Pressure
6.4 Holding Pressure and Time
6.5 Mold Temperature
6.6 Demolding Temperature
6.7 Molded-In Stresses
6.8 Other Molding Processes
References
7. Factors Affecting Postmold Shrinkage and Warpage
7.1 Effects of Temperature on Dimensions
7.2 Effects of Moisture on Dimensions
7.3 Creep
References
8. Controlling Mold and Postmold Shrinkage and Warpage
8.1 Finding the Cause
8.2 Processing Considerations
8.3 Material Considerations
8.4 Tooling Considerations
8.5 Part Geometry
8.6 Controlling Warpage
References
9. Computer-Aided Analysis
9.1 Capabilities of CAA
9.2 Limitations of CAA
9.3 Selecting a CAA Program
9.4 Customer Requirements
9.5 Management Tools
9.6 Filling Analysis
9.7 Packing and Holding Simulation
9.8 Shrinkage/Warpage Simulation
9.9 Cooling Analysis
9.10 Costs
9.11 Conclusions
References
10. Case Studies
10.1 Unexpected Housing Shrink
10.2 Changing Materials Triggers Warpage
10.3 Creep in a Water Heater Stand
10.4 Oversize Part Injection-Molding Alkyd Thermoset
10.5 Inadequate Baby Dish Mold
10.6 Gas Entrapment in Baby Dish Mold
10.7 Warpage in a Molded Spool
10.8 Daisy-Wheel Breakage
10.9 PVC Part-Flashing Problems
10.10 Polycarbonate Switch Failure
10.11 Square Poker-Chip Tray: Inadequate Shot Size
10.12 Problem Ejecting Square Poker Chips
10.13 Military Cup Material “Shrinkage”
10.14 Core-Deflection Problems
10.15 Elevator Gib Warpage
10.16 Sucker-Rod Guide Brittleness
10.17 Bottle-Cap Thread Distortion
10.18 Plastic Post Creep
10.19 Excessive Shrinkage of Glass-Filled Nylon
10.20 Preventing Warpage in Thin Molded Lids
10.21 A Printed Circuit Board That Did Not Work
10.22 A Cup with a Handle that Won’t Fill
10.23 Leaking Hot Runner Mold
References
11. Data
11.1 Unfilled Materials
11.2 Effects of Fillers
11.3 Shrinkage vs. Various Parameters
11.4 Moisture Absorption Curves
11.5 Pressure–Volume–Temperature Curves
11.6 Shrinkage and Warpage of Molded Disks
11.7 Angular Warpage
11.8 General Shrinkage Characteristics for Various Plastics
11.9 Material-Specific Shrinkage Characteristics
References
Appendix A. Conversion Factors and Equivalents
Appendix B. Abbreviations, Acronyms, and Material Names
B.1 Abbreviations and Acronyms
B.2 Material Names
Glossary
Index
Color Plates
- No. of pages: 292
- Language: English
- Edition: 2
- Published: December 26, 2012
- Imprint: William Andrew
- Hardback ISBN: 9781455725977
- eBook ISBN: 9781455730575
JF
Jerry Fischer
Affiliations and expertise
Tools and Troubleshooting, Inc.Read Handbook of Molded Part Shrinkage and Warpage on ScienceDirect