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How Plastics are Made Understanding the Physical Properties of Plastics

How Plastics are Made Understanding the Physical Properties of Plastics. Prepared by the IAPD Education Committee (Module 1) Presented courtesy of Modern Plastics, Inc. Processing. Hand (or spray) lay up Laminating Filament winding Polymer orientation. Injection molding

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How Plastics are Made Understanding the Physical Properties of Plastics

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  1. How Plastics are Made Understanding the Physical Properties of Plastics Prepared by the IAPD Education Committee (Module 1) Presented courtesy of Modern Plastics, Inc. The IAPD Plastics Primer, Module 1

  2. Processing • Hand (or spray) lay up • Laminating • Filament winding • Polymer orientation • Injection molding • Extrusion • Ram extrusion • Screw extrusion • Coextrusion • Casting • Compression molding • Rotational molding • Transfer molding • Calendering The IAPD Plastics Primer, Module 1

  3. Injection Molding The IAPD Plastics Primer, Module 1

  4. Extrusion • Ram • Screw • Coextrusion The IAPD Plastics Primer, Module 1

  5. Casting Base Material Reactive Additive Oven Casting Mold The IAPD Plastics Primer, Module 1

  6. Mold Lid Mold Resin Compression Molding • Sheet and block molding • Parts molding The IAPD Plastics Primer, Module 1

  7. Rotational Molding • Low cost • Low pressure • Used in many markets • Easily adapted for short production runs The IAPD Plastics Primer, Module 1

  8. Transfer Molding Widely used in the semiconductor industry The IAPD Plastics Primer, Module 1

  9. Calendering The IAPD Plastics Primer, Module 1

  10. Hand (or Spray) Lay Up • Used to make large parts • Used to produce fiberglass boats and camper shells The IAPD Plastics Primer, Module 1

  11. Laminating Resin Binder Reinforcing Substrate Heat and pressure applied to the top and bottom of the material The IAPD Plastics Primer, Module 1

  12. Filament Winding • Used to make containers and tubes • Items used for transportation of liquids or gasses The IAPD Plastics Primer, Module 1

  13. Polymer Orientation Used to manufacture polymer fibers, strapping, webbing, film, sheet and profiles The IAPD Plastics Primer, Module 1

  14. Plastics Fabrication • CNC machining centers • CNC lathes • Cutting and drilling • Profiling • Routing and milling • Thermoforming • Forging • Milling • Welding • Bending • Bonding The IAPD Plastics Primer, Module 1

  15. Thermoforming • Single station thermoforming • Rotary station thermoformers • Pressure forming • Twin sheet thermoforming The IAPD Plastics Primer, Module 1

  16. Welding • Extrusion welding • Hot gas welding • Butt welding • Spin welding • Solvent welding The IAPD Plastics Primer, Module 1

  17. Bonding The union of materials by adhesives; to unite materials by means of an adhesive The IAPD Plastics Primer, Module 1

  18. The Performance of a Plastic Part is Affected By: • Type of load • Size and application of load • Frequency of application of load • Speed of load • Temperature the part will see, and for how long • Use and environment of load The IAPD Plastics Primer, Module 1

  19. Mechanical Properties • Torsional strength • Modulus • Impact strength • Specific gravity • Water absorbtion • Coefficient of Friction (COF) • Tensile strength • Elongation • Compressive strength • Creep • Shear strength • Flexural strength The IAPD Plastics Primer, Module 1

  20. Testing Organizations • AFNOR - Association Francaise de Normalisation (France) • BSI - British Standards Institution (UK) • IEC - International Electrotechnical Commission • JIS - Japanese Industrial Standards The IAPD Plastics Primer, Module 1

  21. Tensile Strength The IAPD Plastics Primer, Module 1

  22. Elongation The IAPD Plastics Primer, Module 1

  23. Compressive Strength • Measured in pounds per square inch (PSI) • Higher PSI = harder to compress The IAPD Plastics Primer, Module 1

  24. Creep • Associated with compressive strength • Creep at room temperature is called “cold flow” The IAPD Plastics Primer, Module 1

  25. Shear Strength The IAPD Plastics Primer, Module 1

  26. Flexural Strength The IAPD Plastics Primer, Module 1

  27. Torsional Strength The IAPD Plastics Primer, Module 1

  28. Modulus • Also referred to as “stiffness” • Used in conjunction with strengths (flexural modulus, tensile modulus, etc.) • Higher modulus = stiffer material • Measured in PSI The IAPD Plastics Primer, Module 1

  29. Izod Impact Tensile Impact Gardner Impact Impact Strength The IAPD Plastics Primer, Module 1

  30. Specific Gravity • Related to the density of material • Can be used to determine the weight of material • Specific gravity of less than 1.0 will float in water The IAPD Plastics Primer, Module 1

  31. Water Absorption • Measured by the percentage of swell • Think of a sponge as having high percentage absorption The IAPD Plastics Primer, Module 1

  32. Coefficient of Friction (COF) • Resistance to sliding (slickness) • Low COF = more slippery (think of “wet ice” as having lowest COF) • Static COF refers to initial movement from rest • Dynamic COF refers to being already in motion The IAPD Plastics Primer, Module 1

  33. Thermal Properties • Coefficient of thermal expansion • Heat deflection temperature • Continuous service temperature • Melting point • Thermal conductivity The IAPD Plastics Primer, Module 1

  34. Coefficient of Thermal Expansion (CTE) • Change in size as temperature changes • Lower value = less change with temperature The IAPD Plastics Primer, Module 1

  35. Heat Deflection Temperature (HDT) • Temperature up to which a material can perform, under load, without distorting • Measured in degrees Fahrenheit, usually under 264 PSI • Used most widely to predict performance The IAPD Plastics Primer, Module 1

  36. Continuous Service Temperature (CST) • Highest temperature a material can withstand and still retain at least 50% of its properties • Measured in degrees Fahrenheit, in air • In high temperatures, both CST and HDT must be considered The IAPD Plastics Primer, Module 1

  37. Melting Point Temperature at which a crystalline thermoplastic changes from solid to liquid The IAPD Plastics Primer, Module 1

  38. Thermal Conductivity • How much heat a material will conduct • Most plastics are good “insulators” (do not conduct heat well) • Higher value = more heat conducted • Thermal conductivity of plastics is 300 to 2,500 times less than most metals The IAPD Plastics Primer, Module 1

  39. Electrical Properties • Volume resistivity • Surface resistivity • Dielectric constant • Dielectric strength • Dissipation factor • Arc resistance • Flammability The IAPD Plastics Primer, Module 1

  40. Volume Resistivity • Ability of electricity to flow through a material • Measured in ohms/cm • Lower value = more easily current flows • Higher value = better resistor or insulator The IAPD Plastics Primer, Module 1

  41. Surface Resistivity • Ability of electricity to flow over the surface of a material • Same measurements as volume resistivity • Used to evaluate material when static discharge characteristics are critical The IAPD Plastics Primer, Module 1

  42. Surface Resistivity Insulative Range Conductive Range Static Dissipative Range 20 9 10 11 12 1 2 3 4 5 1 10 10 10 10 10 10 10 10 10 10 Shielding Range 6 7 8 10 10 10 106 to 108 Critical Range for ESD Control The IAPD Plastics Primer, Module 1

  43. Dielectric Constant That property of a dielectric that determines the electrostatic energy stored per unit volume for unit potential gradient The IAPD Plastics Primer, Module 1

  44. Dielectric Strength • Effectiveness of material as an insulator • Measured in volts/.001 thickness • Higher value = better insulator • Voltage is increased until material arcs, showing a breakdown The IAPD Plastics Primer, Module 1

  45. Dissipation Factor Tangent of the loss angle of the insulating material The IAPD Plastics Primer, Module 1

  46. Arc Resistance Time required for an arc to establish a conductive path on the surface of an organic material The IAPD Plastics Primer, Module 1

  47. Flammability • Measured by UL94 ratings • Most favorable ratings are given to materials that extinguish themselves rapidly, and do not drip flaming particles • Scale from highest burn rate => most flame retardant is HB, V-2, V-1, V-0, 5V The IAPD Plastics Primer, Module 1

  48. The IAPD Plastics Primer, Module 1

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