E-Book, Englisch, 282 Seiten
ISBN: 978-3-446-41855-4
Verlag: Carl Hanser
Format: PDF
Kopierschutz: 1 - PDF Watermark
Contents:
General Forming Concepts
Part Design
Machinery for the Thick-Gauge Forming Process
Machinery for the Light-Gauge Forming Process
Machines for Other Applications
Molds and Mold Design
Methods of Heating Sheet
Sheet Stretching and Cooling
Trimming
Polymers and Plastics
Quality Control
Comparison with Other Technologies
Pragmatic Aspects of Thermoforming
Autoren/Hrsg.
Fachgebiete
- Technische Wissenschaften Verfahrenstechnik | Chemieingenieurwesen | Biotechnologie Technologie der Kunststoffe und Polymere
- Technische Wissenschaften Verfahrenstechnik | Chemieingenieurwesen | Biotechnologie Mechanische und Thermische Verfahrenstechnik
- Technische Wissenschaften Maschinenbau | Werkstoffkunde Produktionstechnik Fertigungstechnik
Weitere Infos & Material
1;Foreword to the Second Edition;5
2;Contents;8
3;1 Introduction to Thermoforming;16
3.1;1.1 Brief History;16
3.2;1.2 General Markets;18
3.3;1.3 Terminology;20
3.4;1.4 General Characteristics of Thermoformed Products;21
4;2 General Forming Concepts;24
4.1;2.1 Heating and Bending;24
4.2;2.2 Simple Heating and Stretching;26
4.3;2.3 One-Step Forming;26
4.3.1;2.3.1 Drape Forming;26
4.3.2;2.3.2 Vacuum Forming;27
4.3.3;2.3.3 Free Forming;27
4.3.4;2.3.4 Non-Uniform Heating;28
4.3.5;2.3.5 Matched Mold Forming;28
4.4;2.4 Other One-Step Forming Processes;29
4.4.1;2.4.1 Autoclave Forming;29
4.4.2;2.4.2 Diaphragm Forming;29
4.5;2.5 Two-Step Forming;30
4.5.1;2.5.1 Pneumatic Preforming;30
4.5.2;2.5.2 Plug Assisted or Mechanical Preforming;32
4.5.3;2.5.3 Pressure Forming;34
4.5.4;2.5.4 Coining;34
4.6;2.6 Three-Step Forming;34
4.7;2.7 Twin-Sheet Forming;35
4.7.1;2.7.1 Heavy-Gauge Twin-Sheet Forming;35
4.7.2;2.7.2 Light-Gauge Twin-Sheet Forming;37
4.8;2.8 Contact Forming;39
4.9;2.9 Thermoforming as a Portion of the Overall Manufacturing Process;40
5;3 Part Design;42
5.1;3.1 Part Design Philosophy;42
5.1.1;3.1.1 Design Protocol;43
5.1.2;3.1.2 Project Protocol;44
5.2;3.2 Should This Part Be Thermoformed?;45
5.3;3.3 General Parameters Affecting Part Design;46
5.3.1;3.3.1 Shrinkage;46
5.4;3.4 General Product Design;49
5.4.1;3.4.1 Corner versus Chamfer;50
5.4.2;3.4.2 Draft Angles;50
5.4.3;3.4.3 Thermal Expansion;51
5.4.4;3.4.4 Dimensional Tolerance;52
5.4.5;3.4.5 Improving Dimensional Tolerance;54
5.5;3.5 Part Surface Quality;55
5.6;3.6 Trim Line Location;56
5.7;3.7 In-Mold Decorating and Labeling;57
5.8;3.8 Seal Designs on Twin-Sheet Thermoformed Parts;58
5.9;3.9 Some Guidelines to Successful Part Design;59
6;4 Machinery for the Thick-Gauge Forming Process;64
6.1;4.1 Shuttle Press;64
6.1.1;4.1.1 Two-Oven Shuttle Press;65
6.2;4.2 Cabinet Press;66
6.3;4.3 Rotary Thermoforming Press;66
6.4;4.4 The Elements of Heavy-Gauge Machinery;68
6.4.1;4.4.1 Sheet Handling;69
6.4.2;4.4.2 Sheet Clamping;69
6.4.3;4.4.3 Sheet Shuttle or Rotation;69
6.4.4;4.4.4 Oven(s);69
6.4.5;4.4.5 The Forming Press;70
6.4.6;4.4.6 Pneumatic Prestretching;71
6.4.7;4.4.7 Plug Assist Prestretching;71
6.4.8;4.4.8 Load/Unload Elements;72
6.4.9;4.4.9 Vacuum Box and Vacuum System;72
6.4.10;4.4.10 Pressure Box and Pressurization System;73
6.4.11;4.4.11 Condition Monitors and Process Control;74
6.4.12;4.4.12 Safety Elements;76
7;5 Machinery for the Light-Gauge Forming Process;78
7.1;5.1 Standard Roll-Fed Machine;78
7.2;5.2 Contact Heater Machines;80
7.3;5.3 Form-Fill-Seal Operation;80
7.4;5.4 Elements of Light-Gauge Machinery;82
7.4.1;5.4.1 Sheet Take-off or Unwind Station;82
7.4.2;5.4.2 Pin-Chain and Pin-Chain Rail;82
7.4.3;5.4.3 Oven(s);83
7.4.4;5.4.4 The Forming Press;84
7.4.5;5.4.5 Plug Assist Prestretching Devices;86
7.4.6;5.4.6 Trim Means;86
7.4.7;5.4.7 In-Machine Stacking Means;87
7.4.8;5.4.8 Vacuum Box and Vacuum System;87
7.4.9;5.4.9 Pressure Box and Pressurization System;88
7.4.10;5.4.10 Trim or Web Take-up Station;89
7.4.11;5.4.11 Condition Monitors and Process Control;89
7.4.12;5.4.12 Safety Features;91
8;6 Machines for Other Applications;92
8.1;6.1 Extrusion-Forming Lines;92
8.1.1;6.1.1 Advantages of Extrusion-Forming Lines for Heavy-Gauge Forming;92
8.1.2;6.1.2 Advantages of Extrusion-Forming Lines for Light-Gauge Forming;93
8.1.3;6.1.3 Disadvantages of Extrusion-Forming Lines for Heavy-Gauge Forming;93
8.1.4;6.1.4 Disadvantages of Extrusion-Forming Lines for Light-Gauge Forming;93
8.1.5;6.1.5 Important Extruder Characteristics in In-Line Forming;94
8.2;6.2 Matched Mold Forming Machines;94
8.2.1;6.2.1 Foamed Polymer Machines;95
8.2.2;6.2.2 Composite and Composite Laminate Machines;95
8.3;6.3 Wheel Machines;96
8.4;6.4 Custom Machines;97
8.5;6.5 Twin-Sheet Forming Machines;98
9;7 Molds and Mold Design;100
9.1;7.1 Production Mold Materials;100
9.1.1;7.1.1 Cast Aluminum;100
9.1.2;7.1.2 Machined Aluminum;102
9.1.3;7.1.3 Other Production Mold Materials;102
9.2;7.2 Prototype Mold Materials;103
9.2.1;7.2.1 Hardwoods;103
9.2.2;7.2.2 Plaster;103
9.2.3;7.2.3 Medium-Density Fiberboard;104
9.2.4;7.2.4 Syntactic Foam;104
9.2.5;7.2.5 Thermoset Plastics;105
9.2.6;7.2.6 Sprayed Metal;105
9.3;7.3 Mold Design Elements;105
9.3.1;7.3.1 Cooling;105
9.3.2;7.3.2 Venting;106
9.3.3;7.3.3 Undercuts;107
9.3.4;7.3.4 Mold Surface Texture;108
9.3.5;7.3.5 Textured Mold or Textured Sheet?;109
9.4;7.4 Plug Assist Materials and Designs;109
9.5;7.5 Other Mold Features;112
9.5.1;7.5.1 Cavity Isolators or Grids and Perimeter Clamps;112
9.5.2;7.5.2 Pressure Box;112
9.5.3;7.5.3 Draw Box;113
9.5.4;7.5.4 Coining;113
9.5.5;7.5.5 Web Breakers and Chasers;113
9.5.6;7.5.6 Rapid Tool Change;114
9.6;7.6 Molds for Matched Mold Forming;115
9.7;7.7 Molds for Twin-Sheet Forming;115
10;8 Methods of Heating Sheet;116
10.1;8.1 General Heating Concepts;116
10.1.1;8.1.1 Conduction;116
10.1.2;8.1.2 Convection;118
10.1.3;8.1.3 Radiation;119
10.2;8.2 Common Thermoforming Heaters;121
10.2.1;8.2.1 Convection or Hot Fluid Heating;121
10.2.2;8.2.2 Electric Heaters;122
10.2.3;8.2.3 Combustion Heating;125
10.2.4;8.2.4 Contact Heating;127
10.3;8.3 Selecting the Proper Heater;128
10.4;8.4 A Comparison of Widely Used Heaters;130
10.5;8.5 Heating Cycle Time;132
10.5.1;8.5.1 Forming Temperature Range;132
10.5.2;8.5.2 Energy Uptake;133
10.5.3;8.5.3 Polymer Characteristics;134
10.5.4;8.5.4 Geometric Factors;135
10.5.5;8.5.5 The Issue of Sheet Sag;136
10.5.6;8.5.6 Heating Composites, Laminates, and Other Plastics;137
10.5.7;8.5.7 Pattern or Zonal Heating;138
10.5.8;8.5.8 One-Sided versus Two-Sided Heating;139
10.5.9;8.5.9 Heating Cycle Time Prediction;141
10.5.10;8.5.10 Equilibration;141
11;9 Sheet Stretching and Cooling;144
11.1;9.1 Modulus and Stiffness;144
11.2;9.2 The Concept of Viscoelasticity;145
11.2.1;9.2.1 Elasticity;145
11.2.2;9.2.2 Viscosity;145
11.2.3;9.2.3 Viscoelasticity;146
11.2.4;9.2.4 Measuring Viscoelastic Properties of Polymers;147
11.3;9.3 The Concepts of Stress and Strain;148
11.3.1;9.3.1 The Forming Window;149
11.3.2;9.3.2 Forming Area Diagram;150
11.4;9.4 Prestretching;151
11.5;9.5 Pressure Forming;152
11.6;9.6 The Effect of Sheet Cooling;153
11.6.1;9.6.1 Forming Area Diagrams for Laminates and Composites;153
11.6.2;9.6.2 Differential Stretching against a Mold Surface;153
11.7;9.7 Draw Ratios;154
11.7.1;9.7.1 The Usefulness of Draw Ratios;155
11.7.2;9.7.2 Wall Thickness Reduction in Laminates;155
11.8;9.8 Part Wall Thickness Prediction;157
11.8.1;9.8.1 Finite Element Analysis;157
11.8.2;9.8.2 FEA Data Input;158
11.8.3;9.8.3 Model Verification;159
11.9;9.9 Sheet Sag and Sag Rate;160
11.10;9.10 Cooling Against a Mold Surface;161
11.10.1;9.10.1 Light-Gauge Cooling Criteria;162
11.10.2;9.10.2 Heavy-Gauge Cooling Criteria;162
11.10.3;9.10.3 Cooling and Residual Stress;162
11.10.4;9.10.4 Coolant Characteristics;162
11.10.5;9.10.5 Coolant Flow Rate and Temperature Control;163
11.11;9.11 Cooling Against the Plug;164
11.12;9.12 Heat Removal by Mold and Coolant;164
11.13;9.13 Forming Times;165
12;10 Trimming;168
12.1;10.1 The Mechanics of Trimming;169
12.2;10.2 Light-Gauge Trimming;170
12.2.1;10.2.1 In-Mold Trimming;170
12.2.2;10.2.2 In-Machine Trimming;173
12.2.3;10.2.3 In-Line Trimming;173
12.2.4;10.2.4 Two-Step Trimming;175
12.3;10.3 Prototype Trimming;176
12.4;10.4 Heavy-Gauge Trimming;177
12.4.1;10.4.1 In-Plane Trimming;177
12.4.2;10.4.2 Hand Power Tool Trimming;179
12.4.3;10.4.3 Milling or 3-Axis Machines;179
12.4.4;10.4.4 Multi-Axis Routers;180
12.4.5;10.4.5 Robotic Trimmers;180
12.5;10.5 The Importance of the Trim Fixture;181
12.5.1;10.5.1 Cutter Design;181
12.6;10.6 Trim Tolerance;182
12.7;10.7 Other Trimming Concepts;183
12.7.1;10.7.1 Water Jet Cutting;183
12.7.2;10.7.2 Laser Cutting;184
12.7.3;10.7.3 Trimming Foam;184
13;11 Polymers and Plastics;186
13.1;11.1 Polymer Characterization;186
13.1.1;11.1.1 Plastic vs. Polymer;186
13.1.2;11.1.2 Thermoset and Thermoplastic Definitions;187
13.1.3;11.1.3 Crystalline and Amorphous Definitions;187
13.1.4;11.1.4 Homopolymers, Copolymers, Terpolymers, and Blends;188
13.1.5;11.1.5 Additives, Fillers and Reinforcements;188
13.2;11.2 The Thermoforming Window;190
13.3;11.3 Thermoformable Polymers;191
13.3.1;11.3.1 Polystyrene and Other Styrenics;191
13.3.2;11.3.2 Polyvinyl Chloride and Other Vinyls;192
13.3.3;11.3.3 Acrylics;193
13.3.4;11.3.4 Cellulosics;194
13.3.5;11.3.5 Polycarbonate;194
13.3.6;11.3.6 Polyesters;195
13.3.7;11.3.7 Polyethylene;197
13.3.8;11.3.8 Polypropylene;198
13.3.9;11.3.9 Other Polyolefins;202
13.3.10;11.3.10 Formable Biopolymers;204
13.3.11;11.3.11 Other Formable Polymers;206
13.4;11.4 Multilayer Polymers;208
13.5;11.5 Foamed Plastics;209
13.5.1;11.5.1 High-Density Foams;209
13.5.2;11.5.2 Low-Density Foams;211
13.6;11.6 Thermal Properties;213
13.6.1;11.6.1 Heat Capacity;214
13.6.2;11.6.2 Thermal Conductivity;214
13.6.3;11.6.3 Polymer Density;215
13.6.4;11.6.4 Thermal Diffusivity;215
13.6.5;11.6.5 Thermal Coefficient of Expansion;215
13.6.6;11.6.6 Thermal Properties of Multilayer Structures, and Filled and Reinforced Polymers;216
13.7;11.7 Infrared Energy Absorption for Specific Polymers;216
14;12 Issues of Quality Control;220
14.1;12.1 Incoming Sheet Quality;220
14.1.1;12.1.1 What the Thermoformer Needs to Know About the Extrusion Process;220
14.1.2;12.1.2 What the Thermoformer Needs to Know About Quality;225
14.1.3;12.1.3 What the Thermoformer Needs to Know About Regrind;230
14.2;12.2 The Role of the Purchase Order;232
14.2.1;12.2.1 Incoming Sheet Quality Evaluation;233
14.3;12.3 Production Monitoring;233
14.3.1;12.3.1 Monitoring Temperature;233
14.3.2;12.3.2 Sheet Formability;234
14.3.3;12.3.3 Cutting Surfaces – Microfracture Concerns;236
14.3.4;12.3.4 Finished Part Performance;236
15;13 Comparison with Other Technologies;238
15.1;13.1 Classification of Plastics Molding Technologies;240
15.2;13.2 Polymer Material Choices;241
15.3;13.3 Other Processing Concerns;241
16;14 Pragmatic Aspects of Thermoforming;244
16.1;14.1 Safety;244
16.2;14.2 Thermoforming Machine Set-Up;247
16.2.1;14.2.1 Set-Up for a New Machine;247
16.2.2;14.2.2 Set-Up for a Used Machine;248
16.3;14.3 Mold Set-Up;249
16.3.1;14.3.1 New Mold Set-Up;249
16.3.2;14.3.2 Existing Mold Set-Up;249
16.4;14.4 Trim Set-Up;250
16.4.1;14.4.1 Heavy-Gauge Trim Set-Up;250
16.4.2;14.4.2 Light-Gauge Trim Set-Up;251
16.5;14.5 Maintenance;251
16.5.1;14.5.1 Emergency Maintenance;251
16.5.2;14.5.2 Preventative Maintenance;252
16.6;14.6 Troubleshooting Tips;254
16.6.1;14.6.1 Non-Crisis Troubleshooting;254
16.6.2;14.6.2 The Crisis Situation;256
17;References;258
18;Recommendations for Further Reading;262
18.1;Books;262
18.2;Other Sources;262
18.3;Historical Reading;263
19;Appendix: Glossary of Thermoforming Terms;264
20;Subject Index;272
