كتاب Practical Guide to Injection Moulding
منتدى هندسة الإنتاج والتصميم الميكانيكى
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منتدى هندسة الإنتاج والتصميم الميكانيكى
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 كتاب Practical Guide to Injection Moulding

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كتاب Practical Guide to Injection Moulding  Empty
مُساهمةموضوع: كتاب Practical Guide to Injection Moulding    كتاب Practical Guide to Injection Moulding  Emptyالجمعة 03 يناير 2020, 10:50 pm

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Practical Guide to Injection Moulding
2nd Edition
Edited by
Vannessa Goodship
A Smithers Group Company  

كتاب Practical Guide to Injection Moulding  P_g_t_16
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Contents
1 Introduction .1
1.1 The Big Picture .1
1.2 Introduction to Injection Moulding 1
1.3 The Injection Moulding Process 3
1.3.1 Piston Injection Unit .4
1.3.2 Reciprocating Screw Machine .5
1.3.3 Breaking Down the Injection Moulding Cycle 7
1.3.3.1 Plastication .7
1.3.3.2 Filling 7
1.3.3.3 Packing and Solidification .8
1.4 Comparison with Other Moulding Methods .9
1.4.1 Extrusion 9
1.4.2 Compression Moulding 9
1.4.3 Transfer Moulding 10
1.4.4 Blow Moulding .10
1.4.5 Film Blowing 12
1.4.6 Injection-Compression 13
1.4.7 Additive Manufacturing .14
1.5 Conclusion .15
1.6 Suggested Further Reading .16
2 Introduction to Plastics .17
2.1 Introduction .17
2.2 Structure and Typical Properties of Polymers 18
2.3 Formation of Macromolecules 20
2.4 Molecular Weight .21
2.5 Plastics 22
2.5.1 Thermoplastic 22
2.5.2 Thermosets 23
2.5.3 Elastomers 24
2.5.3.1 Thermoplastic Elastomers .24
2.5.4 The Formulation of Plastics 25
2.5.5 The Binding Structure of Plastics .26
2.6 The Effects of Processing on Thermoplastics 27
2.6.1 Rheology 27x
ARBURG Practical Guide to Injection Moulding, 2nd Edition
2.6.2 Heat and Heat Transfer 28
2.6.3 Physical and Chemical Change .28
2.6.4 Fountain Flow 29
2.7 Conclusion .30
3 Injection Moulding Machinery .31
3.1 Injection Units 32
3.2 Piston (Plunger) Injection Unit 33
3.3 Reciprocating Screw Injection Unit .33
3.3.1 Shot Capacity .33
3.3.2 Plasticising Capacity .33
3.3.3 The Feeding Hopper .34
3.3.4 The Injection Cylinder 34
3.4 Selection of the Injection Unit .35
3.5 Length/Diameter Ratio .36
3.5.1 Mixing Screws for Additives and Fast Cycling Machines 38
3.5.1.1 Mixing Elements .38
3.5.1.2 Extended Plasticising Cylinder 39
3.5.2 Non-Return Valve .40
3.6 General Information on Wear and Tear 41
3.7 Unit Hardening Treatment 42
3.8 The Nozzle 43
3.9 Clamping Units .46
3.9.1 Differential Piston System .48
3.9.2 Mould Weights .50
3.10 Selection of the Clamping Unit .51
3.11 Mould Clamping Force 51
3.11.1 Mould Clamping Force Level .51
3.11.2 Mould Clamping Force and Mould Rigidity .52
3.11.3 Setting Mould Closing and Clamping Force .52
3.11.3.1 The Clamping Force 52
3.11.3.2 Second Clamping Force 53
3.12 Data for Mould Closing .53
3.13 Other Considerations .57
3.14 International Standard for the Designation of Injection Moulding Machines 57
3.15 Injection Moulding Machine: Drive Technology .58
4 Injection Mould Tooling Basics 61
4.1 Types of Moulds 61
4.1.1 Two-Plate Mould .61
4.1.2 Stripper Mould .62
4.1.3 Slide Mould 63xi
Contents
4.1.4 Three-Plate Mould 63
4.2 The Feed System .66
4.2.1 Introduction .66
4.2.2 The Runner 66
4.2.3 Runner Shape .66
4.2.4 Runner Layout .68
4.2.4.1 Standard-Runner 69
4.2.4.2 Cold-Runner 69
4.2.4.3 Hot-Runner .69
4.3 Gate Design 73
4.3.1 Sprue Gate .73
4.3.2 Restricted Gate .74
4.3.3 Side or Edge Gate .75
4.3.4 Flash Gate 75
4.3.5 Fan Gate .76
4.3.6 Tab Gate .76
4.3.7 Diaphragm Gate .77
4.3.8 Spider Gate .77
4.3.9 Ring Gate .78
4.3.10 Hot Tip Gating .78
4.4 Mould Temperature Control 79
4.5 Ejection Systems .82
4.6 Venting .84
4.7 Conclusion .85
4.8 Suggested Further Reading .85
5 Process Control Systems .87
5.1 Introduction .87
5.2 Explanation of the Different Concepts in Control and Regulation Technology .87
5.2.1 Hydraulic or Electric Systems? 87
5.2.1.1 Pump 87
5.2.2 Motor .88
5.2.3 Cylinder 88
5.2.4 Directional Valves .89
5.2.5 Pressure Valves .91
5.2.6 Flow-Regulator Valves 91
5.2.7 Location and Setting of Proportional Valves .92
5.2.7.1 Valve Bodies 93
5.2.7.2 Function of the Volume Proportional Valve 93
5.2.7.3 Function of the Pressure Proportional Valve .94
5.2.8 Check Valves 95
5.2.9 Receivers 95xii
ARBURG Practical Guide to Injection Moulding, 2nd Edition
5.3 General Information Regarding Control Units, Regulators, Position Regulation and
Injection Process Regulation .96
5.3.1 Control Unit .96
5.3.2 Regulator 97
5.3.3 Screw with Position Regulator 97
5.3.4 Injection Process Regulation .98
5.4 Electrical Systems .101
5.5 Hybrid Machines 103
5.6 The User Interface 103
6 Amorphous and Semi-Crystalline Thermoplastics 107
6.1 Introduction .107
6.2 Amorphous Plastics 108
6.2.1 Overview and Common Properties .109
6.2.2 Standard Polystyrene Homopolymer 110
6.2.3 Styrene Copolymers 110
6.2.4 Modified Polyphenylene Oxide .112
6.2.5 Polyvinyl Chloride 112
6.2.6 Cellulose Materials .114
6.2.7 Polymethyl Methacrylate 115
6.2.8 Polycarbonate .116
6.2.9 Polyacrylates .117
6.2.10 Polysulfones 120
6.2.11 Polyetherimide .120
6.2.12 Polyamide Imide .122
6.3 Semi-Crystalline Plastics .123
6.3.1 Overview and Common Properties 123
6.3.2 Polyethylene .125
6.3.3 Polypropylene .126
6.3.4 Polyamides .127
6.3.5 Polyacetals 129
6.3.6 Polyterephthalates (Linear Polyesters) .131
6.3.7 Polyphenylene Sulfide – Typical Characteristics and Applications .132
6.3.8 Polyfluorolefins .133
6.3.9 Polyacrylic Acid and Polyarylamide 134
6.3.10 Polyacryl and Ether Ketones 137
6.3.11 Liquid Crystalline Polymers .138
6.2 Conclusion .140
7 Processing Thermoset, Liquid Silicone Rubber and Ceramic Materials .141
7.1 Thermosets .141
7.1.1 Overview and Common Properties .141xiii
Contents
7.1.2 Materials for Screw Injection Moulding Machines .142
7.1.3 Processing Procedures for Thermoset Plastics .143
7.1.3.1 Compression Moulding .143
7.1.3.2 Injection Moulding .144
7.1.4 Screw Injection Machines for Thermosets .144
7.1.5 Mould 145
7.1.6 Guide Values for Cylinder and Mould Temperature Settings 145
7.1.7 The Injection Unit for Granulated Thermosets .147
7.1.8 The Injection Unit for Processing Moist Polyester .147
7.1.9 Nozzle Temperature (if Nozzle Heating is Applied) 148
7.1.10 Common Thermoset Materials: Properties and Applications 148
7.1.10.1 Phenol Formaldehyde Compounds 148
7.1.10.2 Urea Formaldehyde Compounds .149
7.1.10.3 Melamine Formaldehyde Compounds .150
7.1.10.4 Unsaturated Polyester .151
7.1.10.5 Epoxide Compounds .152
7.2 Elastomer Injection Moulding Compounds .153
7.2.2 Processing Procedures for Elastomeric Materials 154
7.2.2.1 Compression Moulding .154
7.2.2.2 Injection Moulding .154
7.2.2.3 Injection Moulding Machines for Rubber Compounds .154
7.2.2.4 Peripheral Device 155
7.2.2.5 Mould .155
7.2.3 Silicone Elastomers – Liquid Silicone Rubber Systems .155
7.2.3.1 Classification .156
7.2.3.2 Crosslinking 156
7.2.3.3 Processing of Two-Component Liquid Silicone Rubber .157
7.2.3.4 Advantages of Processing Liquid Silicone Rubber Materials .158
7.2.3.5 Injection Process .158
7.2.3.6 Configuration of Injection Moulding Machines and Processing
Data 158
7.2.3.7 Specific Properties .159
7.2.3.8 Crosslinking Reaction .160
7.2.3.9 Structural Viscosity .161
7.2.3.10 Vulcanisation 162
7.2.3.11 Internal Mould Pressure 163
7.2.3.12 Shrinkage 163
7.2.3.13 Tempering .163
7.2.3.14 Preparation of Liquid Silicone Rubber 163
7.2.4 Processing Components for Liquid Injection Moulding 163
7.2.4.1 Dosing Equipment for Liquid Silicone Rubber 163
7.2.4.2 Machine Technology .166xiv
ARBURG Practical Guide to Injection Moulding, 2nd Edition
7.2.4.3 Injection Unit 166
7.2.4.4 Cylinder Module .167
7.2.4.5 Non-Return Valve .168
7.2.4.6 Auxiliary Heating Control Circuits .169
7.2.4.7 Interface for Brush and Cleaner Units .169
7.2.4.8 Handling Interface 169
7.2.4.9 User-programmable Inputs/Outputs 169
7.2.4.10 Air Blast Equipment with Pressure Reducer 169
7.2.4.11 Control Unit for Vacuum Pump 169
7.2.4.12 Hydraulic/Pneumatic Cold-Runner Control 169
7.2.4.13 Protective Screens Made of Polycarbonate 170
7.2.4.14 Simple Cold-Runner Nozzle 170
7.2.4.15 Cold-Runner Head 170
7.2.4.16 Mould Technology .172
7.2.5 Application of Liquid Silicone Rubber Parts in Food Production 178
7.2.6 Summary 178
7.3 Processing of Ceramic and Metal Powder Materials .179
7.3.1 Introduction .179
7.3.2 Binder .181
7.3.3 Processing .182
7.3.3.1 Compression Moulding .182
7.3.3.2 Injection Moulding .182
7.3.4 Configuration of Injection Moulding Machines 183
7.3.4.1 Peripheral Devices .183
7.3.4.2 Mould .183
7.3.4.3 Wear .183
7.3.5 Process Requirements .183
7.3.5.1 Debinding and Sintering 185
7.4 A Growing Market for Moulders .185
8 Guide Values and Processing Instructions for the Most Important Thermoplastic
Injection Moulding Compounds .187
8.1 Predrying Material 187
8.2 Examples of the Moulding Parameters of Selected Materials .187
8.3 Parameters of the Injection Moulding Process and the Quality of Moulded Parts .190
8.4 Injection and Mould Cavity Pressure 194
8.5 Injection Pressure and Injection Time .197
8.6 General Information on Filling Speed 197
8.6.1 Initial Injection Speed .197
8.7 Filling Speed and Orientation .198
8.8 Effects of Excessive Filling Speed 199
8.9 Setting the Initial Injection Speed 199xv
Contents
8.10 Plasticising 200
8.10.1 Compound Temperature – General Information .200
8.10.2 Cylinder Temperatures 201
8.10.3 Nozzle Temperature 202
8.10.4 Temperature Profile Guideline for the Plasticising Cylinder 202
8.10.4.1 Horizontal 202
8.10.4.2 Ascending .203
8.10.4.3 Descending 203
8.10.4.4 Ascending and Descending at the Nozzle 203
8.10.5 Temperatures for the Cylinder and Mould 204
8.10.6 Measuring the Compound Temperature .206
8.10.7 Screw Speed 207
8.10.8 Back Pressure 207
8.11 The Injection Stage .209
8.11.1 Filling to Packing 209
8.11.2 The Mould .211
8.11.2.1 Mould Temperature: General Information 211
8.11.2.2 Mould Temperature Levels .211
8.11.2.3 Uniformity of Mould Temperatures 212
8.11.2.4 Mould Temperature Patterns 213
8.11.2.5 Temperature Control Devices 213
8.11.2.6 Matching Temperature Control Units and Mould Maintenance 215
8.11.2.7 Measuring the Mould Temperature – Checking the Uniformity of
the Mould Temperature Control .215
8.12 Recommended Values for Holding Pressure Time and Remaining Cooling Time 216
8.13 Cycle Time 218
8.14 Setting the Injection Moulding Machine .218
9 Practical Applications using Injection Moulding Technology 219
9.1 Introduction .219
9.2 Troubleshooting and Guidance .219
9.2.1 Detection and Classification of Defects .220
9.2.2 Flow Diagrams for Troubleshooting .221
9.2.3 Sink Marks .244
9.2.4 Streaks 245
9.2.4.1 Burnt Streaks (Brown or Silver) .248
9.2.4.2 Moisture Streaks .249
9.2.4.3 Colour Streaks 250
9.2.5 Air Streaks/Air Hooks 251
9.2.6 Glass Fibre Streaks .251
9.2.7 Gloss/Gloss Differences 253
9.2.8 Weld Line (Visible Notch or Colour Change) .254xvi
ARBURG Practical Guide to Injection Moulding, 2nd Edition
9.2.9 Jetting .256
9.2.10 Diesel Effect (Burns) .257
9.2.11 Record Grooves Effect 258
9.2.12 Stress Whitening/Stress Cracks .260
9.2.13 Incompletely Filled Parts .261
9.2.14 Oversprayed Parts (Flashes) 263
9.2.15 Visible Ejector Marks .264
9.2.16 Deformation during Demoulding 265
9.2.17 Flaking of the Surface Layer .266
9.2.18 Cold Slugs/Cold Flow Lines 267
9.2.19 Entrapped Air (Blister Formation) 268
9.2.20 Dark Spots 269
9.2.21 Dull Spots near the Sprue .270
9.3 Data Acquisition Record .271
9.3.1 Using the Data Acquisition Record .271
9.3.2 Data Acquisition Record for Optimising Moulded Parts 272
9.3.2.1 Moulded Part Data .272
9.3.2.2 Machine Settings and Defect Evaluation .273
9.4 Experiences with Injection Moulded Components 274
9.4.1 Threaded Connecting Sleeves for Ink-Drafting Apparatus 275
9.4.2 Meter Cases 275
9.4.3 Wristwatch Glass 276
9.4.4 Alarm Clock Glass 277
9.4.5 Glass Cover for a Digital Gauge .277
9.4.6 Plug Boards with Insert Pins .278
9.4.7 Hair Slides 279
9.4.8 Toothbrush Components 280
9.4.9 Screw Cap with Conical Nipple 281
9.4.10 Switch Housing 282
9.4.11 Battery Housing 282
10 Advanced Processing Techniques 285
10.1 Introduction 285
10.2 Multicomponent Moulding 286
10.2.1 Co-injection Moulding .286
10.2.2 Bi-Injection Moulding .286
10.2.3 Interval Injection Moulding .286
10.2.4 Injection Moulding/Additive Manufacturing Hybrid Processes .286
10.3 Assisted Moulding 287
10.4 Multi-Shot Moulding 287
10.5 Over-Moulding .288
10.6 Micromoulding .288xvii
Contents
10.7 Business Trends 288
10.8 Material Selection 290
10.9 Process Technology .292
10.9.1 Multicomponent Injection Moulding 292
10.9.2 Co-Injection Moulding 293
10.9.2.1 Material Selection for Co-Injection Moulding .294
10.9.2.2 Process Sequence .295
10.9.2.3 Co-injection Moulding: Different Techniques .295
10.9.2.4 Part Design and Tooling Requirements for Co-Injection Moulding .300
10.9.2.5 Rheology and Mould Filling: Why and How Co-Injection
Moulding Works .301
10.9.2.6 Setting Optimum Parameters 304
10.9.2.7 Co-Injection Moulded Application Case Studies .305
10.9.2.8 Recycling and Legislation 305
10.9.2.9 Discussion and Conclusions 305
10.9.3 Bi-Injection .306
10.9.4 Interval Injection Moulding 306
10.10 Assisted Moulding 308
10.10.1 Gas Injection Moulding Technology .308
10.10.2 Process Technology .308
10.10.3 Patent Situation 309
10.10.4 Advantages and Disadvantages of Gas Injection Moulding Technology 309
10.10.5 Process Variations in the Application of Gas Injection Moulding Technology .310
10.10.5.1 Gas Injection through the Machine Nozzle .310
10.10.5.2 Gas Injection through an Injector Module in the Mould .311
10.10.5.3 Gas Injection in the Moulded Part .313
10.10.5.4 Melt Blow Moulding Technology 313
10.10.5.5 Melt Back Pressure Technology/Gas Injection in the Moulded Part .314
10.10.5.6 Melt Extrusion Technology/Gas Injection in the Moulded Part .315
10.10.5.7 Core Pull Technology 316
10.10.5.8 Systems Technology for the Implementation of Gas Injection
Moulding Technology .317
10.10.5.9 Configuration Guidelines for Gas Injection Moulding Technology .318
10.10.6 KoolGas™ 320
10.10.7 Water-Assisted Injection Moulding Process .320
10.11 Multi-Shot Moulding 321
10.11.1 Machine Technology .322
10.11.1.1 Injection Unit Configurations 322
10.11.2 Core Back Moulding 324
10.11.3 Rotating Tool .325
10.11.4 Transfer Moulding 327
10.11.5 Multi-Shot using a Single Injection Unit .330xviii
ARBURG Practical Guide to Injection Moulding, 2nd Edition
10.11.6 Materials for Multi-Shot Moulding 330
10.11.6.1 Material Selection for Multi-Shot Moulding .330
10.11.6.2 Material Process Order .331
10.11.6.3 Using Thermoset Materials .331
10.11.6.4 Liquid Silicone Rubber 331
10.11.6.5 Thermoplastic Elastomers .332
10.11.7 Multi-Shot Application Case Studies 333
10.11.7.1 Trio Knob .333
10.11.7.2 Stanley Screwdriver 334
10.11.8 Limitations to Multi-Shot .334
10.12 Over-Moulding .335
10.12.1 Insert Moulding 335
10.12.2 Lost Core Moulding .335
10.13 A Final Word on Energy Efficiency .336
10.14 The Future? 337
Abbreviations .341
Appendix Trade Names, Specific Weight and Suppliers of Some Plastic Materials 345
Index


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