SPI Plastics Engineering Handbook of the Society of the Plastics Industry, Inc.

I am pleased to present the Fifth Edition of the Plastics Engineering Handbook. Last published in 1976, this version of the standard industry reference on plastics processing incorporates the numerous revisions and additions necessitated by 14 years of activity in a dynamic industry. At that last printing, then-SPI President Ralph L. Harding, Jr. anticipated that plastics pro­ duction would top 26 billion pounds in 1976 (up from 1.25 billion in 1947, when the First Edition of this book was issued). As I write, plastics production in the United States had reached almost 60 billion pounds annually. Indeed, the story of the U.S. plastics industry always has been one of phenomenal growth and unparalleled innovation. While these factors make compilation of a book such as this difficult, they also make it necessary. Thus I acknowledge all those who worked to gather and relate the information included in this 1991 edition and thank them for the effort it took to make the Plastics Engineering Handbook a definitive source and invaluable tool for our industry. Larry L. Thomas President The Society of the Plastics Industry, Inc.Table of Content1 Glossary.- 2 Polymer Chemistry.- Forming Polymers.- Polymerization Techniques.- Weight, Size, and Distribution of Molecules.- Polymer Structure.- Effect of Time and Temperature.- Chemical Composition.- 3 Plastic Materials/Properties and Applications.- The Family of Plastics.- Thermoplastic Resins.- The Polyolefins.- Styrenic Plastics.- Vinyl Plastics.- Other Thermoplastics.- Engineering Thermoplastics.- Thermoplastic Elastomers (TPEs).- Alloys and Blends.- Thermosetting Resins.- Alkyds.- Allylics.- Bismaleimides (BMI).- Epoxies.- Melamines.- Phenolics.- Polyesters.- Polyimides.- Silicones.- Ureas.- Polyurethanes.- 4 Extrusion Processes.- Extrusion Concepts.- Single Screw Functional Description.- Feeding and Solids Conveying.- Melting Considerations.- Melt Pumping.- Wear Effects on Pumping.- Mixing.- Devolatilizing (Venting).- Effects of Extruder Accessories.- Twin Screw Vs. Single Screw Operation.- Single Screw Extruder Physical Description.- Barrels.- Heating/Cooling Systems.- Screws.- Thrust Bearings.- Gear Case.- Drive Motor.- Drive Coupling.- Extrusion Controls and Instrumentation.- Basic Control Requirements.- Sensors and Monitors.- Temperature Control.- Pressure Control.- Melt Temperature Control.- Size Controls.- Rate Controls.- Extrusion Processes.- Blown Film.- Sheet, Extrusion Coating, and Cast Film.- Profiles and Pipe.- Wire and Cable.- Fiber.- Extruder Screws.- Extruder Screws (General).- Screw Types.- Screw Cooling.- Mixing Considerations and Mixing Devices.- Scaling Screw Design and Extruder Performance.- Glossary of Extrusion Terms.- 5 Injection Molding of Plastics.- Overview.- Injection Ends.- Melting a Plastic in a Screw.- Clamping Ends.- Circuits.- Automation.- Material Handling.- Secondary Operations.- Safety.- Coloring.- Multicylinder Machines.- Theory of Injection Molding.- Properties of Linear and Branched Materials.- Crystallinity.- Flow Properties.- Orientation.- Shrinkage.- Correcting Molding Faults.- Process Control.- On-Machine Monitoring.- Temperature Control of Barrel and Melt.- PID Injection Pressure Control.- Relating Process Control to Product Performance.- Molding Parameters.- Display of Monitored Molding Parameters.- Machine Control.- Adaptive Ram Programmer.- Microprocessor Advantages.- Glossary of Injection Molding Terms.- 6 Design Considerations for Injection Molds.- Mold Design Features.- Two-Plate Mold.- Three-Plate Mold.- Hot Runner Molds.- Insulated Runner Molds.- Runners.- Gates.- Moldmaking.- Venting.- Parting Line.- Ejection.- Ejector Mechanisms.- Ejector Sleeve.- Stripper Ring.- Stripper Plates.- Vent Pins.- Cam Actions.- Early Ejector Return Unit.- Mold Cooling.- Standard Equipment.- Standard Mold Bases.- Standard Cavity Inserts.- 7 Injection Mold Manufacturing.- The Moldmaker.- Design and Consideration.- Number of Cavities.- Machine Size.- Plasticizing Capacity.- Economics.- Specifications.- Features.- Mold Quotations.- Delivery Time.- Placement.- Responsibilities.- Standard Mold Bases.- Mold Plates.- Mold Base Nomenclature.- “A” Series Mold Bases.- Mold Base Stainless Steel.- Window Pockets.- Blind Pockets.- Cavity Pockets.- Wear Plates.- Mold Base Machining.- Special Mold Bases.- Quality of Mold Bases.- Mold Base Numbers.- Specific-Purpose Mold Bases.- “AX” Mold Bases.- “T” Series Mold Bases.- Mold Base Features.- Mold Base Plates.- Types of Molds.- Conventional Molds.- Three-Plate Molds.- Insulated Runner Molds.- Internally Heated Runnerless Molding Systems.- Externally Heated Runnerless Molding Systems.- Runnerless Molding Nozzles.- Valve-Gate Runnerless Molding Systems.- Fabrication of Components.- Cavity Machining.- Core and Cavity.- Electric-Discharge Machining.- Slide and Unscrewing Devices.- Collapsible Cores.- Collapsible Core Sequence.- Mold Components.- Interlocks.- Return Pins and Springs.- Early Ejector Return.- External Positive Return System.- Hobbing.- Cast Cavities.- Electroforming.- Cavity Finishing.- SPI Finish Number.- Hand Benching.- Tool-Assisted Benching.- Direction of Benching.- Mold Polishing.- Ultrasonic Tools.- Textured Cavities.- Texture Patterns.- Mold Steels.- Compression Molds.- Transfer Molds.- Reaction Injection Molds.- Expandable Polystyrene Molds.- Structural Foam Molds.- Chrome Plating.- Electroless Nickel Plating.- Nitriding and Carburizing.- Proprietary Wear Processes.- Mold Steel.- 8 Injection Molding of Thermosets.- Overview.- How the Process Operates.- Process and Design Considerations.- Materials.- Process Effects on Design.- Injection-Compression Molding.- Part-Design Considerations.- Cold Runner Molding.- Injection Molding Reinforced Polyesters.- Injection Molding Presses.- Temperature Control.- 9 Compression and Transfer Molding.- Compression Molding.- Techniques and Materials.- Molding of Phenol-formaldehyde Components.- Molding of Urea-formaldehyde and Melamine-formaldehyde Components.- Molding of General Purpose Polyester Molding Compounds.- Molding of Alkyd Materials.- Molding of Thermoplastic Materials.- Molding of Fluorocarbons.- Cold Molding.- Advantages of Compression Molding.- Limitations of Compression Molding.- Procedure for Compression Molding.- Types of Compression Molds.- Machinery and Equipment.- Automatic Compression Molding.- Basic Requirements for Automatic Compression Molding.- Types of Machines.- Preheating in Automatic Compression Molding.- Transfer Molding.- History.- Utility of Process.- Description of Process.- Transfer Molds.- Advantages of Transfer Molding.- Limitations of the Process.- Comparison between Compression and Transfer Molding.- Theoretical and Design Considerations.- Liquid Resin Molding.- 10 Designing Molds for Thermoset Processing.- Method of Molding.- Compression Molds.- Transfer Molds.- Injection Molding of Thermosets.- Injection-Compression Molding of Thermosets.- Runner and Gate Design.- Vents.- General Mold Design Considerations.- 11 Molded Part Design.- Structural Design Characteristics of Plastics.- Mechanical Properties—The Stress-Strain Curve.- Effect of Temperature, Loading Time, and Environment.- Creep and Relaxation.- Design Methods.- Designing Within the Modulus Accuracy Limit.- Yield Design.- Designing the Part.- Basic Design Theory.- Wall Thickness.- Fillets and Radii.- Ribs.- Undercuts.- Taper or Draft.- Bosses/.- Holes.- External and Internal Threads.- Inserts.- Parting Lines.- Surface Treatment.- Molded Lettering.- Avoiding Warpage Problems.- Design.- Mold Design.- Molding Conditions.- Troubleshooting Guide.- 12 Blow Molding of Thermoplastics.- Extrusion Blow Molding.- Process Variables.- Die Dimension Calculations.- Air Entrance.- Parison Variations.- Types of Extrusion Blow Molding.- Continuous Extrusion.- Intermittent Extrusion.- Forced Extrusion.- Dip Blow Molding.- Form/Fill Seal.- Coextrusion Blow Molding.- Trimming and Handling.- Neck Calibration.- In-Mold Labeling.- Materials.- Injection Blow Molding.- Design Considerations.- Coinjection Blow Molding.- Stretch Blow Molding.- Injection Orientation Blow Molding.- Coinjection Stretch Blow Molding.- Auxiliary Equipment.- Molds for Extrusion Blow Molding.- Injection Blow Molding Cooling.- Design and Construction.- Principle of Operations.- Mold Design.- Alignment of Components.- Core Rod Design and Construction.- Parison Molds.- Blow Molds.- 13 Thermoforming of Plastic Film and Sheet.- Overview.- Methods of Thermoforming.- Methods of Thermoforming.- Vacuum Forming into a Female Mold.- Pressure Forming into Female Cavity.- Free Forming.- Plug-Assist Forming.- Drape Forming.- Matched Mold Forming.- Trapped Sheet.- Plug-and-Ring Forming.- Ridge Forming.- Slip Forming.- Snap-Back Forming.- Billow-Up Prestretch Techniques.- Billow-Up Plug Assist (or Reverse Draw with Plug Assist).- Billow-Up Vacuum Snap-Back.- Dual Sheet Forming.- Thermoforming Machines.- Single-Stage, Sheet-Fed Machines.- Multiple-Stage, Sheet-Fed Machines.- In-Line Sheet-Fed Machines.- Continuous Roll-Fed Machines.- Packaging Machines.- Materials.- Plastic Memory.- Hot Elongation or Hot Strength.- Temperature Range for Forming.- Thermoforming Processing Temperatures.- Heating.- Temperature Control.- Vacuum/Air Pressure.- Tooling.- Trimming.- Problems of Shrinkage.- Trimming in the Mold.- Control.- Manual-Control Equipment.- Automation.- Control Systems.- Thermoforming of Coextruded Structures and Other Special Materials.- Cooling Requirements of the Thermoforming Process.- Substrate Thermoforming.- Troubleshooting.- Checklist for Troubleshooting.- Thermoforming Troubleshooting Guide.- 14 Rotational Molding.- Overview.- How It Works.- Machinery.- Batch-Type Machines.- Carousel-Type Machines.- Independent-Arm-Type Machines.- Straight-Line Machines.- Jacketed-Mold Machines.- Molds.- Materials.- Design.- 15 Calendering.- Blending.- Scrap and Cold Trim.- Mills and Strainers.- Calender.- Take-Off Stripper Section.- Embo