3. Extrusion, injection moulding, compression moulding, vacuum forming and laminating are examples of common manufacturing processes used with polymers (Plastics). Choose one process and with the use of diagrams and bullet points outline the process.
Injection Moulding
- Materials such as polystyrene, nylon, polypropylene and polythene can be used in injection moulding. These are all thermoplastics - when they are heated they can be manipulated into a mould and form different shapes
- Lego bricks are made by injection moulding.
- Here are the steps for injection moulding.
1. Plastic powder grandules are poured or fed into a hopper which stores it until it is needed.
2. A heater heats up the tube and when it reaches a high temperature a screw thread starts turning.
3. A motor turns a thread which pushes the granules along the heater section which melts then into a liquid. The liquid is forced into a mould where it cools into the shape (in this case its lego bricks)
4. The mould then opens and the brick is removed (after it has cooled down).
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