Thermoforming

Auteur

Muralisrinivasan Natamai Subramanian has an extensive background in research & development (R&D) in the polymer industry. Throughout his career, he has demonstrated leadership by heading R&D teams and providing consultancy services to the polymer industry across different countries. Notably, he has successfully devised an organizational model for the technical team, resulting in increased research activities and enhanced satisfaction among polymer industries. Additionally, Dr. Muralisrinivasan has played a pivotal role in the integration of medium-scale companies within the sector. With a remarkable dedication of 33 years to the plastics industry, including 22 years as a consultant, he has conducted numerous training programs for various companies. He has authored 16 books on plastics engineering and technology, covering a wide range of topics such as troubleshooting in plastics processing, plastics additives and testing, plastics blends and composites, and electroactive polymers. His extensive knowledge encompasses polymer materials, machinery, testing, and applications.

Texte du rabat

This book is a comprehensive reference manual that contains essential information on thermoforming processing and technology. The field of thermoforming is experiencing rapid development driven by commercial factors; millions of tons of polymers are manufactured for use in various applications, both as commodity and specialty polymers. Building on the previous edition published about ten years ago, this edition includes new, as well as, fully revised chapters and updated information on materials and processes. The book is designed to provide practitioners with essential information on processing and technology in a concise manner. The book caters to both engineers and experts by providing introductory aspects, background information, and an overview of thermoforming processing and technology. The troubleshooting section includes flowcharts to assist in correcting thermoforming processes. "Thermoforming: Processing and Technology" offers a complete account of thermoplastics, covering properties and forming, with chapters providing perspective on the technologies involved. Readers will find it:

• serves as a handy knowledge source for professionals who occasionally work on thermoforming projects or need to refresh their knowledge;
• offers a troubleshooting guide that can help to identify and solve challenges that may arise in thermoforming processes;
• provides insights into process optimization, helping businesses improve efficiency, reduce waste, and enhance the quality of thermoformed products;
• acts as a course book to inform students about the thermoforming process. Audience The book will be of interest to mechanical, materials engineers, and process engineers who are involved in designing and optimizing thermoforming processes; professionals in the manufacturing and production industries who use thermoforming as a manufacturing method, such as in the production of plastic packaging, automotive components, and consumer goods; scientists, researchers, and students in plastics/polymer engineering and technology, materials science, polymer technology; professionals responsible for ensuring product quality and compliance with industry standards.

Contenu

Preface xiii

1 Introduction 1

2 Polymers 5

2.1 Introduction 5

2.2 Physics and Chemistry of Polymers 6

2.3 Natural Polymers 6

2.4 Synthetic Polymers 7

2.5 Polymerization Methods 8

2.5.1 Addition Polymerization 8

2.5.2 Condensation Polymerization 9

2.6 Polymer Molecules in Thermoforming 10

2.7 Classification 11

2.8 Primary Classification 11

2.8.1 Homopolymers 11

2.8.2 Copolymers 12

2.8.2.1 Block Copolymers 13

2.8.2.2 Diblock Copolymers 16

2.8.2.3 Multiblock Copolymers 16

2.8.3 Alternating Copolymers 17

2.8.4 Random Copolymers 18

2.8.5 Graft Copolymers 18

2.8.6 Impact Copolymers 19

2.9 Secondary Classification 20

2.9.1 Thermoplastics 20

2.9.2 Thermosetting Plastics 22

2.10 Distinction Between Thermoplastics and Thermosetting 22

2.11 General Classification 23

2.11.1 Commodity Plastics 23

2.11.2 Engineering Plastics 24

3 Thermoplastics 27

3.1 Introduction 27

3.2 Polyolefins 27

3.3 Polyethylene 28

3.3.1 Low Density Polyethylene (LDPE) 29

3.3.2 High-Density Polyethylene (HDPE) 30

3.3.3 Linear-Low-Density Polyethylene (LLDPE) 32

3.4 Polypropylene 33

3.5 Polystyrene (PS) 37

3.6 High-Impact Polystyrene (HIPS) 39

3.7 Polyvinylchloride 40

3.8 Acrylonitrile-Butadiene-Styrene (ABS) 41

3.9 Polyethylene Terephthalate (PET) 44

3.10 Acrylics 45

3.10.1 Polymethylmethacrylate (PMMA) 46

3.11 Nylon 6 (PA6) 48

3.12 Nylon 66 (PA66) 49

3.13 Polyoxymethylene (POM) 50

3.14 Polycarbonate (PC) 51

3.15 Poly(ether-ether-ketone) (PEEK) 53

3.16 Polyphenylene Oxide (PPO) 54

3.17 Polybutylene Terephthalate (PBT) 55

3.18 Liquid Crystalline Polymers 57

3.19 Cyclic Olefin Copolymer (COC) 57

3.20 Plastic Foams 58

3.21 Thermoplastic Elastomers 60

3.21.1 Thermoplastic Olefin (TPO) 60

3.21.2 Thermoplastic Urethane (TPU) 61

3.22 Thermoplastic Composites (TCs) 62

3.23 Bioplastics 65

3.23.1 Polylactic Acid (PLA) 65

3.23.2 Poly(Butylene Succinate) (PBS) 67

4 Properties of Thermoplastic Sheet Materials 69

4.1 Introduction 69

4.2 Polymer Characteristics 69

4.3 Polymer Morphology 70

4.3.1 Amorphous Polymers 71

4.3.2 Semi-Crystalline Polymers 72

4.3.3 Crystalline Polymers 74

4.3.4 Amorphous Versus Semi-Crystalline Polymers 75

4.4 Molecular Structure 76

4.5 Molecular Weight 77

4.6 Molecular Weight Distribution 77

4.7 Melt Flow Index 78

4.8 Glass Transition Temperature 79

4.9 Melt Temperature 82

4.10 Heat Deflection Temperature (HDT) 83

4.11 Crystallization Temperature 84

4.12 Melt Strength 86

4.13 Rheological Properties 89

4.14 Viscoelastic Behavior 89

4.15 Coefficient of Friction 92

4.16 Thermal Conductivity 93

4.17 Thermal Diffusivity 94

4.18 Specific Heat 95

4.19 Stress 96

4.20 Strain Hardening 97

4.21 Plastic Strain 99

4.22 Tensile Strain 100

4.23 Tensile Yield Stress 101

4.24 Deformation 102

4.25 Stress Deformation 104

4.26 Modulus and Stiffness 106

4.27 Sag 107

4.28 Toughness 107

4.29 Effect of Additives 108

5 Thermoforming Technology 111

5.1 Introduction 111

5.2 Thermoplastic Sheet Materials 111

5.3 Mechanical Characteristics 112

5.4 Thermoformability 113

5.5 Thermoforming Cycle 114

5.6 Draw Ratio 115

5.7 Processing Window 116

5.8 Mold 118

5.9 Mold Design 119

5.10 Heating Elements 123

5.10.1 Infrared Heaters 124

5.10.2 Flash Heaters 125

5.10.3 Forced Convection Hot Air Heating 125

5.10.4 Other Heaters 126

5.11 Plug Material 127

5.12 Plug Design 128

5.13 Product Design 129

5.14 Clamping 131

5.15 Process Control 132

5.16 Process Variables 133

5.17 Thermal History 138

5.18 Pre-Drying 140

5.19 Plug Movement 140

5.20 Plug Speed 141

5.21 Sheet Temperature 141

5.22 Mold Temperature 143

5.23 Forming Temperature 144

5.24 Wall Thickness Distribution 144

5.25 Sheet Deformation 145

5.26 Heat Transfer 146

5.27 Effects of Temperature Distribution 147

5.28 Effect of Drawing 147

5.29 Effect of Frictional Force 148

5.30 Effect of Plug-Assist/Vacuum 148

5.31 Effect of Applied Pressure 149

5.32 Effect of Heating 150

5.33 Effect of Cooling 151

5.34 Rate of Deforming 153

5.35 Rate of Sagging 154

5.36 Effect of Air Temperature 155

5.37 Effect of Air Pressure 155

5.38 Effect of Crystallinity and Morphology 157

5.39 Processing Technology 158

5.39.1 Heating Stage 159

5.39.2 Sheet Heating 159

5.39.3 Forming Stage 160

5.39.4 Draw Ratio 160

5.39.5 Cooling Stage 160

5.40 …