Handbook of Molded Part Shrinkage and WarpageThe 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 tells why you never can have a single ""correct"" shrinkage value. But that's not all. The handbook shows how to alleviate the problem by 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. This is the most complete collection of shrinkage data ever made and includes an extensive compilation of hard-to-find multi-point information on how processing, part design, mold design, material and post mold treatment affect the part's final dimensions. Manufacturers' figures for thousands of grades, along with an exhaustive search of magazines, journals, conference papers, books, web sites and brochures combine to make this a powerful resource. A lot depends on a dimensionally correct molding. Quality, speed to market, profit margins for the molder and toolmaker, the efficiency of secondary and assembly operations, reputation; all these are on the line. The Mold Shrinkage and Warpage Handbook is the book for people who have to live with shrinkage and warpage. It is the only book for people who have to commit themselves. |
Contents
Chapter 1 Introduction to Plastics Processing | 1 |
Chapter 2 Shrinkage and Warpage | 9 |
Part Design | 17 |
Material | 23 |
Mold Design | 51 |
Processing | 79 |
Chapter 7 Factors Affecting PostMold Shrinkage and Warpage | 97 |
Chapter 8 Controlling Mold and PostMold Shrinkage and Warpage | 105 |
Chapter 9 ComputerAided Analysis | 127 |
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Common terms and phrases
Acetal Amorphous analysis annealing cause cavity pressure Celanese clamping cooling channels core pin Courtesy of DuPont Courtesy of SPE cross-flow shrinkage crystalline crystallization cycle Delrin Density diameter differential shrinkage dimensional dimensions effect ejection fiber orientation Figure fill fillers flow direction flow front gate freezes GE Plastics glass fiber glass-fiber heat holding pressure Hytrel in-flow increase injection molding injection pressure injection-molded Lexan melt moisture mold builder mold cavity mold design mold shrinkage mold temperature molded-in stresses molder molding conditions molding machine molding process molecular molecules nozzle nylon perature plaque plastic polycarbonate Polyethylene polypropylene Polystyrene post-mold shrinkage programs PVT diagram reduce reinforced resin result ribs Rynite semicrystalline semicrystalline materials semicrystalline polymer shear shear rate shown in Fig shows shrink rate shrinkage and warpage side sprue Styrene thermal thermoplastics thicker tion tolerances tool Transverse unfilled uniform variations wall thickness warp Zytel