Gastrow Injection Molds 4E: 130 Proven Designs / Edition 4

by Peter Unger

Overview

Designing the perfect mold is probably the most challenging task in plastics processing, especially in injection molding. The mold determines the quality, performance, and the profitability of a plastic part. Neither modern computer technology nor sophisticated CAE soft ware can substitute the experience of the practicing mold engineer. This is why the “Gastrow” is so special to plastics engineers: 130 mold designs are presented in this extensively revised edition of the great classic in mold making. Each of the case studies was actually built, tested, and run successfully in production. The book is written by practitioners, describing problem solving in the design and the manufacture of injection molds. The wealth of information includes rules of thumb, design details, and practical tips invaluable for everyone involved in this field.

Product Details

ISBN-13:	9781569904022
Publisher:	Hanser Publications
Publication date:	06/01/2006
Edition description:	4th Revised ed.
Pages:	335
Product dimensions:	7.30(w) x 10.40(h) x 0.80(d)

Table of Contents

1 Principles of Mold Design 1

1.1 Types of Injection Molds 1

1.2 Types of Runners and Gates 2

1.2.1 Solidifying Systems 2

1.2.2 Hot Runner Systems 6

1.2.3 Cold Runner Systems 10

1.2.3.1 Molds for Processing Elastomers 10

1.2.3.2 Molds for Processing Thermosets 11

1.3 Temperature Control in Injection Molds 14

1.4 Types of Ejectors 16

1.5 Types of Undercuts 18

1.6 Special Designs 18

1.6.1 Molds with Fusible Cores 18

1.6.2 Prototype Molds of Aluminum 18

1.6.3 Prototype Molds Made of Plastics 19

1.7 Status of Standardization for Injection Molds 19

1.7.1 Standardized Mold Components (as of Mid-2005) 20

1.7.2 Standardized Electrical Connections for Hot Runner Molds 20

1.7.3 Terminology Standards for Injection Molds 20

1.7.3.1 DIN ISO 12165 "Tools for Molding-Components of Compression and Injection Molds and Die-Casting Dies" 20

1.7.3.2 DIN 16769 "Components for Gating Systems - Terms" 21

1.7.4 DIN ISO 16916 "Tools for Molding - Tool Specification Sheet for Injection Molds" 22

1.8 Standard Mold Components 22

1.9 Injection Mold for Producing Test Specimens from Thermoplastic Resins 22

1.10 Materials Selection 23

1.10.1 General Requirements for Materials 23

1.10.2 Tool Steels 24

1.10.2.1 Case-Hardening Steels 24

1.10.2.2 Prehardened Steels 24

1.10.2.3 High-Speed Steels 26

1.10.2.4 Corrosion Resistant Steels 26

1.10.2.5 Powder-Metallurgical (PM) Steels 27

1.10.2.6 Cast Ferrous Materials 27

1.10.3 Non-Ferrous Metals 27

1.10.3.1 Aluminum Alloys 27

1.10.3.2 Titanium Alloys 28

1.10.3.3 Copper Alloys 28

1.10.4 Anorganic Nonmetallic Materials 29

1.10.4.1 Ceramic Materials 29

1.10.5 Surface Treatment Methods 29

1.10.5.1Nitriding 30

1.10.5.2 Carburizing 30

1.10.5.3 Hard Chrome Plating 30

1.10.5.4 Hard Nickel Plating 30

1.10.5.5 Hard Materials Coating 31

1.11 Materials Properties under Mechanical Stress 32

1.11.1 Notch Effect under Static Stress 32

1.11.2 Notch Effect under Dynamic Stress 33

1.12 Thermal Insulation and Reflector Plates 34

References in Chapter 1 35

2 Special Design Features of the Example Molds 37

3 Examples 41

3.1 Single-Cavity Injection Mold for a Polyethylene Cover 41

3.2 Two-Cavity Injection Mold for Elbow Connector Made from PA 66 43

3.3 Injection Mold for the Body of a Tape-Cassette Holder Made from High-Impact Polystyrene 46

3.4 Five-Cavity Injection Mold for Tablet Tubes Made from Polystyrene 48

3.5 Four-Cavity Injection Mold for a Polyamide Joint Element 50

3.6 Mold Base with Interchangeable Inserts to Produce Standard Test Specimens 52

3.7 Two-Cavity Rotary Core Mold for a Polyacetal Pipe Elbow 54

3.8 Hot Runner Injection Mold for Car Front Fender 58

3.9 Injection Mold for Magnifying Glass Frame with Handle 60

3.10 16-Cavity Hot-Runner Mold for Cover Caps with Segmented Internal Contours Made from Polypropylene (PP) or Polyethylene (PE) 62

3.11 Four-Cavity Injection Mold for a Housing Made from Acrylonitrile-Butadiene-Styrene (ABS) 64

3.12 Four-Cavity Injection Mold for a Nozzle Housing Made from Polyamide 66

3.13 Single Split Cavity Mold for a Threaded Plug Made from Polyacetal (POM) 68

3.14 Demolding a Polyethylene Container with External Undercuts 70

3.15 Injection Mold with Reduced Opening Stroke for Milk Crates from Polyethylene 70

3.16 Two-Cavity Injection Mold for Recessed Refrigerator Handles Made from Polyamide 72

3.17 Injection Mold for a Grass Catcher Made from Polypropylene 75

3.18 Injection Mold for Hose Connectors Made from Polyamide 6.6 77

3.19 Two-Cavity Injection Mold for the Coil Form of an Auxiliary Relay 79

3.20 Single-Cavity Hot-Runner Mold for Business Card Boxes Made from Polypropylene 81

3.21 8-Cavity Injection Mold for Threaded Rings Made from Polyacetal (POM) 83

3.22 Mold for a Pump Housing and Pump Piston Made from Polyacetal 85

3.23 Hot-Runner Injection Mold for Two Film Spools Made from High-Impact Polystyrene 87

3.24 Injection Mold for an Angle Fitting from Polypropylene 90

3.25 Mold for Bushings from Polyamide with Concealed Gating 90

3.26 Injection Mold for the Valve Housing of a Water-Mixing Tap Made from Polyacetal 91

3.27 Mold for a Lid with Three Threads Made from Polyacetal 93

3.28 Two-Cavity Injection Mold for Coupling Sleeves Made from Polyamide 95

3.29 Injection Mold for the Housing of a Polypropylene Vegetable Dicer 97

3.30 Two-Cavity Injection Mold for a Polypropylene Toy Tennis Racket 101

3.31 Two Injection Molds with Two-Step Ejection Process for Housing Components from Polycarbonate 103

3.32 Injection Mold for a Polypropylene Container with a Threaded Neck 107

3.33 Three-Plate Injection Mold with Stripping Device for a Precision Magazine 109

3.34 6-Cavity Metal-Powder Injection Mold (MIM) for Transport Fasteners 111

3.35 Mold for a Polyamide V-Belt Pulley 113

3.36 2 x 8-Cavity Hot-Runner Stack Mold for Yoghurt Cups Made from Polypropylene 115

3.37 2 x 2-Cavity Stack Mold for Covers Made from Polypropylene 117

3.38 2 x 5-Cavity Stack Mold for Cases Made from Polypropylene 119

3.39 16-Cavity Hot-Runner Mold for Packaging of Medical Parts made from Polypropylene 123

3.40 Hot-Runner Stack Mold for a Water Distribution Block Made from Polypropylene 126

3.41 2 x 8-Cavity Stack Mold for Lozenge Box Made from Polystyrene 131

3.42 Two-Cavity Injection Mold for a Tail Light Housing Made from ABS 134

3.43 2 x 2-Cavity Stack Mold with a Hot-Runner System for Runnerless Molding of Polystyrene Container Lids Using Direct Edge Gating 138

3.44 2 x 4-Cavity Hot-Runner Stack Mold for Dessert Cups Made from Polypropylene 142

3.45 Hot-Runner Mold for Bumper Fascia Made from Thermoplastic Elastomer 144

3.46 Four-Cavity Hot-Runner Mold for Threaded Covers Made from SAN 146

3.47 Two-Cavity Hot-Runner Mold for Trim Bezels Made from ABS 148

3.48 Four-Cavity Hot-Runner Mold for Control Flap Made from Polyacetal Copolymer 150

3.49 64-Cavity Hot-Runner Mold for Seals Made from Thermoplastic Elastomer (TPE) 152

3.50 Eight-Cavity Hot-Runner Mold for PP Toothpaste Dispenser 154

3.51 2-Cavity Hot-Runner Mold for Polyethylene Jars 156

3.52 Two-Cavity Hot-Runner Mold for Production of Connectors Made from Polycarbonate 159

3.53 Four-Cavity Hot-Runner Unscrewing Mold for Cap Nuts Made from Polyacetal (POM) 161

3.54 Four-Cavity Hot-Runner Mold with a Special Ejector System for a Retainer Made from Polypropylene 163

3.55 Example 55, 2 x 16-Cavity Two-Component Injection Mold for Microswitch Covers Made from Polyamide and Thermoplastic Elastomer 167

3.56 32-Cavity Hot-Runner Mold for Production of Packings Made from Polyethylene 171

3.57 12-Cavity Hot-Runner Mold with Edge Gates for Bushings Made from Polyacetal Copolymer 173

3.58 Single Injection Mold for Sleeves Made from Glass-Fiber and Talcum Reinforced PA 66 175

3.59 Two-Component Injection Mold for Drink Can Holders Made from Polypropylene and Ethylene-Propylene Terpolymer 177

3.60 Hot-Runner Mold for Polypropylene Clamping Ring with Internal Undercut around the Circumference 180

3.61 Injection Mold for Compact Discs Made from Polycarbonate 183

3.62 Single-Cavity Injection Compression Mold for a Cover Plate Made from Unsaturated Polyester Resin 185

3.63 Two-Cavity Injection Compression Mold for a Housing Component Made from a Thermosetting Resin 187

3.64 Injection Compression Mold for a Plate Made from Melamine Resin 189

3.65 Five-Cavity Unscrewing Mold for Ball Knobs Made from a Phenolic Resin 190

3.66 Four-Cavity Injection Mold for a Thin-Walled Housing Made from a Phenolic Resin 191

3.67 Thermoset Injection Mold for a Bearing Cover Made from Phenolic Resin 194

3.68 6-Cavity Hot-Runner Mold for Coffee Cup Covers Made from Polypropylene 196

3.69 Two Injection Molds for Overmolding of Polyamide Tubing for Automobile Power Window Operators 200

3.70 Single-Cavity Injection Mold for a Housing Base Made from Polycarbonate 202

3.71 Connector with Opposing Female Threads Made from Glass-Fiber-Reinforced Polyamide 204

3.72 Cylindrical Thermoplastic Container with Reduced-Diameter Opening - A Study in Part Release 206

3.73 Single-Cavity Injection Mold for a Lighting Fixture Cover Made from Polymethylmethacrylate (PMMA) 208

3.74 Injection Mold for a Housing with a Thread Insert Made from Polycarbonate 210

3.75 Mold for Long, Thin, Tubular Parts Made from Polystyrene 212

3.76 Insulated Runner Mold for Three Specimen Dishes Made from Polystyrene 214

3.77 Single-Cavity Injection Mold for a Polypropylene Emergency Button 216

3.78 Eight-Cavity Injection Mold for Battery Caps with Undivided External Thread and Sealing Cone Made from Polypropylene 218

3.79 Injection Mold for a Curved Pouring Spout Made from Polypropylene 220

3.80 Injection Mold for an ABS Goggle Frame 222

3.81 4-Cavity Hot Runner Mold for Front Ring 224

3.82 Two-Cavity Two-Component Injection Mold for a PC/ABS Bezel with a PMMA Window 227

3.83 Two-Cavity Injection Mold for Runnerless Production of Polycarbonate Optical Lenses 229

3.84 Injection Mold with Hydraulic Core Pull for a Cable Socket 231

3.85 Four-Cavity Injection Mold for Pipets Made from PMMA 233

3.86 Two-Cavity Mold for Water Tap Handles Made from PMMA 235

3.87 Two-Cavity Injection Mold for the Automatic Molding of Conveyor Plates onto a Wire Cable 237

3.88 20-Cavity Hot-Runner Mold for Producing Curtain-Ring Rollers Made from Polyacetal Copolymer 239

3.89 Injection Mold with Attached Hydraulic Core Pull for Automatic Measuring Tubs Made from PC 241

3.90 48- and 64-Cavity Hot-Runner Molds for Coating Semi-finished Metal Composite with Liquid Crystalline LCP Polymer (Outsert Technology) 243

3.91 24-Cavity Hot-Runner Injection Mold for Polyacetal Spool Cores 247

3.92 Two-Cavity Hot-Runner Mold for Loudspeaker Covers Made from Polyacetal 249

3.93 Injection Mold with Air Ejection for Polypropylene Cups 251

3.94 Molds for Manufacturing Optical Lenses Made from PC 253

3.95 Two-Cavity Injection Mold for a Polycarbonate Steam Iron Reservoir Insert 255

3.96 Injection Mold with Pneumatic Sprue Bushing for a Headlight Housing Made from Polypropylene 258

3.97 Injection Mold for a Mounting Plate (Outsert Technique) 261

3.98 Twelve-Cavity Hot-Runner Mold for a Polyphthalamide (PPA) Microhousing 263

3.99 Two-Cavity Injection Mold for Handle Covers Made from Glass-Fiber-Reinforced Polyacetal 265

3.100 Four-Cavity Injection Mold for Thin-Walled Sleeves Made from Polyester 268

3.101 Injection Mold for a Microstructure Made from POM 270

3.102 Injection Mold for Production of Adjustable Climate Control Vents via 3-Shot Molding 272

3.103 Two-Cavity Hot-Runner Injection Mold for an ABS Cover 276

3.104 Six-Cavity Injection Mold for Retaining Nuts Made from Polyamide with Metal Inserts 278

3.105 Single-Cavity Injection Mold for a Switch Housing Made from Polyacetal 280

3.106 Single-Cavity Injection Mold for a Snap Ring Made from Polyacetal 282

3.107 Single-Cavity Hot-Runner Injection Mold for High-Density Polyethylene (PE-HD) Trash Can Lids 284

3.108 Single-Cavity Hot-Runner Injection Mold for an Air Vent Housing Made from Acrylonitrile Butadiene Styrene (ABS) 287

3.109 Single-Cavity Hot-Runner Injection Mold for an ABS Housing 290

3.110 Single-Cavity Runnerless Injection Mold for a Polystyrene Junction Box 292

3.111 Four-Cavity Hot-Runner Injection Mold for a Polyamide 6,6 Joining Plate 294

3.112 2 x 4-Cavity Hot-Runner Stack Mold for Hinged Covers 296

3.113 16-Cavity Mold with Cold-Runner System for Liquid Silicone Rubber (LSR) Caps 298

3.114 Two-Cavity Injection Mold for a Styrene-Acrylonitrile Safety Closure 300

3.115 Four-Cavity Unscrewing Mold for Threaded Polypropylene Closures 302

3.116 Four-Cavity Injection Mold for Polyester Dispenser Heads 304

3.117 Two-Cavity Injection Mold for PMMA Lighting Fixture Cover 306

3.118 Two-Cavity Injection Mold for Polyacetal Hinges 308

3.119 Eight-Cavity Injection Mold for PE-HD Threaded Caps 310

3.120 4-Cavity Hot-Runner Mold for Connectors Made from Polystyrene 312

3.121 Single-Cavity Mold for a Polypropylene Cutlery Basket 314

3.122 Two-Cavity Injection Mold for Cover Plates Made from Polyacetal 318

3.123 Single-Cavity Injection Mold for a Joystick Baseplate Made from PA 66 320

3.124 Single-Cavity Injection Compression Mold for Thermoset V-Belt Pulley (Injection Transfer Mold) 323

3.125 16-Cavity Hot-Runner Mold for Paperclips Made from ABS 325

3.126 Single-Cavity Injection Mold for a PE-HD Clothes Hanger Produced via Gas-Assisted Injection Molding 327

3.127 Single-Cavity Injection Mold for a Syringe Shield Produced via Metal Injection Molding (MIM) 329

3.128 Three-Station Mold for a Handtool Handle Made from PP/TPE 331

3.129 Four-Cavity Injection Mold for Couplings Produced via Metal Injection Molding (MIM) 334