Injection moulding

1. Injection moulding 120061910 Hamada s. El-Turk

2. Types of Plastic Processing Injection Moulding – Usually for thermoplastics. Molten plastics are injected under pressure into a mould. The mould surface detail (profile of the product) can be accurately reproduced. Compression Moulding – Usually for thermosetting plastics. Plastic is moulded under pressure before the polymerisation begins. Extrusion – Usually for thermoplastics. The molten plastics are fed under pressure by a screw through a hole or a die. Long continuous lengths, such as sheets, rods and tubes, can be produced

3. Injection moulding: The process is used to produce large quantities of identical plastic items. One of the most common types of thermoplastics used in injection moulding is high impact polystyrene (HIPS) though nylon, polypropylene and polythene can also be used. Injection Moulding can produce such small products as bottle tops. Due to the high cost of the machines and the moulds the process is only suitable for long term production runs, once the machines are in place the production method is relatively cheap.

4. Injection molding Similar to extrusion barrel is heated Pellets or granules fed into heated cylinder Melt is forced into a split-die chamber Molten plastic pushed into mold cavity Pressure ranges from 70 Mpa – 200 Mpa Typical products : Cups, containers, housings, tool handles, knobs, electrical and communication components, toys etc.

5. Injection Molding Machine • Main Components:

6. Cont. Main Components: Injection system Mold system Clamping system Controls

7. The Steps

8. Advantages Tight tolerance parts Complex geometry Various surface textures Highly repeatable process Low cost in high volume production Automated process, low labor cost Net shape Parts consolidation