Rotational Molding TechnologyBy
- Roy Crawford
- R.J. Crawford
- James Throne
- James Throne
This book clarifies and quantifies many of the technical interactions in the process. It distinguishes itself from other books on the subject by being a seamless story of the advanced aspects of the rotational molding process. There are seven chapters within the book. The US market for rotational molding products was one billion pounds in the year 2000. The growth of the rotational molding industry has grown at 10 to 15% per year. With this growth has come an increasing need for details on the complex, technical aspects of the process.
Engineers and technicians at manufacturing companies in the plastics industry that employ rotational molding technology processes.
Hardbound, 327 Pages
Published: December 2001
Imprint: William Andrew
- 1.0 Introduction 1.1 The Process 1.2 The Early Days 1.3 Materials 1.4 Advantages and Disadvantages 1.5 General Relationships between Processing Conditions and Properties2. Rotational Molding Polymers 2.0 Introduction 2.1 General Characteristics of Polymers 2.2 Polymers as Powders and Liquids 2.3 Polyethylene Types 2.4 Polypropylene 2.5 PVC û Plastisols, Drysols, and Powdered Flexible Compounds 2.6 Nylons 2.7 Other Polymers 2.8 Liquid Polymers 2.9 In-Coming Material Evaluation 2.10 Product Testing Protocols and Relationship to Polymer Characteristics 2.11 Desirable Characteristics of a Rotational Molding Resin3. Grinding and Coloring 3.0 Introduction 3.1 General Issues Relating to Grinding 3.2 Particle Size Distribution 3.3 Particle Shape 3.4 Dry Flow 3.5 Bulk Density 3.6 Factors Affecting Powder Quality 3.7 Grinding Costs 3.8 Micropelletizing 3.9 Polyvinyl Chloride 3.10 Coloring of Plastics for Rotational Molding4. Rotational Molding Machines 4.0 Introduction 4.1 Types of Rotational Molding Machines 4.2 Machine Design Considerations 4.3 The Oven 4.4 Cooling 4.5 Process Monitors 4.6 Servicing 4.7 Advanced Machine Design 5. Mold Design 5.0 Introduction 5.1 Mold Materials 5.2 Mechanical and Thermal Characteristics of Mold Materials 5.3 Mold Design 5.4 Calculation of Charge Weight 5.5 Venting 5.6 Mold Surface Finish 5.7 Mold Releases6. Processing 6.0 Introduction to Heating 6.1 General Anatomy of the Rotational Molding Cycle 6.2 General Process Description 6.3 Powder Behavior 6.4 Characteristics of Powder Flow 6.5 Rheology of Powder Flow 6.6 Heat Transfer Concepts Applied to Rotational Molding 6.7 Heating the Mold 6.8 Heating Powder 6.9 Tack Temperature 6.10 Mold Cavity Air Heating Prior to Powder Adhesion to Mold Surface 6.11 Bed Depletion 6.12 Particle Coalescence 6.13 Densification 6.14 Phase Change During Heating 6.15 The Role of Pressure and Vacuum 6.16 Mathematical Modeling of the Heating Process 6.17 Total Oven Cycle Time 6.18 Cooling and the Optimum Time for Removal from Oven 6.19 Some Comments on Heat Transfer During Cooling 6.20 Thermal Profile Inversion 6.21 Cooling and Recrystallization 6.22 Air Cooling û Heat Removal Rate 6.23 Water Cooling û Heat Removal Rate 6.24 Pressurization 6.25 Part Removal 6.26 Effect of Wall Thickness on Cooling Cycle Time 6.27 Overview and Summary of Thermal Aspects of the Rotational Molding Process 6.28 Introduction to Liquid Rotational Molding 6.29 Liquid Polymers 6.30 Liquid Rotational Molding Process 6.31 Process Controls for Liquid Rotational Molding 6.32 Foam Processing 7. Mechanical Part Design 7.0 Introduction 7.1 Design Philosophy 7.2 General Design Concepts 7.3 Mechanical Design 7.4 Design Properties of Foams 7.5 Computer-Aided Engineering in Rotational Molding 7.6 Some General Design Considerations 7.7 Process Effects on Porosity, Impact Strength 7.8 Trimming 7.9 Surface Decoration 7.10 Troubleshooting and Quality AssuranceAppendicesIndex