Mp 1-unit - v - processing of plastic components
- 2. ORGANIC MATERIALS Natural – Wood, Coal, Petroleum & Natural Rubber Synthetic – Plastics, Synthetic rubber, Ceramics & Glass Organic material - Polymers
- 3. Polymers Poly means ‘Many’ & ‘Mers’ means ‘Parts’ Polymer built of several repeating units(Monomer) Monomer – small molecules Polymer is made up of thousands of monomers jointed together to form large molecule. Plastics – Organic polymer
- 4. Polymerization process A Polymer is made up of linking thousands of monomer and thus obtaining large molecule is called Polymerization process Additives – Plasticizers (liquid form) – Water, Organic solvents & resins Catalyst – Promote faster & complete Polymerization Dyes – Impart desired colour Initiators – Initiate the reaction (H2O2) Hydrogen peroxide
- 5. Plastics Can be moulded into required shape with the help of pressure or heat or both heat and pressure Resin – liquid form of plastics, also raw material for making plastics Types of resin: acrylic resin, Polyethylene resin & amino resin – Produced by polymerization process Catalysts, Binders & Lubricants added with resin to form plastics
- 6. Modifiers – To improve the mechanical properties of plastics Lubricants – To reduce friction during processing , Avoid sticking to mould walls(Oils, Soaps and waxes) Solvents – Dissolve fillers or Plasticizers & Allow the processing in fluid state(Alcohol) Fillers – Mica, Cloth fiber Elastomers – To enhance the elastic properties
- 7. Properties of Plastics Elongation Heat resistance High rigidity Surface hardness High viscosity Density Chemical resistance
- 8. Thermosetting Plastics Thermosetting - Plastics which are hardened by heat effecting non reversible chemical change . Molecules are formed by condensation polymerization process. All the molecules have three dimensional network and very strong binding force between molecules Bakelite, Polyester resin, Epoxy resin(Araldite), Silicones, Urea formaldehyde(Amino resin) & Alkyds
- 9. Thermo Plastics Have separate long and large size molecule arranged side by side When thermoplastics are heated it becomes very soft and rehardens on cooling During heating the linear bonding links between molecules are breakup and separated. Relinking takes place on cooling and retains their hardness. Cellulose nitrate – pen bodies, Table tennis balls, Frames Ethyl cellulose – Jigs, Fixtures, hose nozzles Cellulose acetate - Radio cabinets, steering wheels, Insulating tapes
- 10. Synthetic resins Polyethylene – Fabrics, tray, pipes, tubing chemical containers & corrosion resistant coatings Polystyrene - Battery boxes, radio parts, toys Vinyles(PVC) – Tarpaulin, Water roofing, raincoats, tubes Polytetra fluroethylene (Teflon)- Gaskets, Greaseless bearing, Electrical insulators, Chemical containers Polyamide(Nylon) – Gears, wire insulation, combs, Bearings and couplings
- 11. S. No Thermoplastics Thermosetting plastics 1 Softened by heating Cannot be softened by heating 2 Structure is made of linear chain molecule Structure is made of cross- linked molecule 3 Produced by addition polymerization process Produced by condensation polymerization process 4 Can be reproduced by heating and cooling Cannot be reproduced 5 When the temp increases the plasticity also increases Plasticity is stable at high temperature 6 Softer and less strong Harder and strong 7 Scrap can be reused Scrap can not be reused
- 12. INJECTION MOULDING 1) RAM OR PLUNGER TYPE INJECTION MOULDING
- 13. THERMOPLASTICS - INJECTION MOULDING 2) SCREW TYPE INJECTION MOULDING
- 14. THERMOPLASTICS – INDUSTRIAL APPLICATION 2) BLOW MOULDING
- 15. THERMOPLASTICS – INDUSTRIAL APPLICATION 3) ROTATIONAL MOULDING
- 16. THERMOPLASTICS – INDUSTRIAL APPLICATION 4) FILM BLOWING
- 17. THERMOPLASTICS – INDUSTRIAL APPLICATION 5) SHEET MAKING
- 18. THERMOPLASTICS – INDUSTRIAL APPLICATION 6) EXTRUSION PROCESS
- 19. THERMOPLASTICS – INDUSTRIAL APPLICATION 7) VACUUM FORMING PROCESS ( THERMO FORMING)
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