Plastics are the cheapest raw materials available in the market. Plastic gets in to proper shape and size by the process of Injection Moulding. Plastic injection moulding is the process of manufacturing of plastic components. Plastic is an economical material which is used in various applications. Plastic Injection moulding is a process of forcing molten plastic by the application of pressure.
Plastic in the form of powder or liquid is fed through hopper into the barrel which is heated up to certain temperatures where it is mixed and then forced through a nozzle with the help of a plunger to the mould cavity where it hardens by cooling and sets to the configuration of the mould. The plunger is used to force the heated raw material through the nozzle. The plunger which is usually used is a ram or a screw-type. The mould is designed and made from steel or aluminium, and then precision machined forming the desired parts. Plastic Injection moulding is used to manufacture various parts, varying from small components to whole body of a vehicle. Manufacturing a mould is very expensive, so a mould is only used for mass productions. Moulding is the process of shaping a raw-material into the desired shape, by applying pressure. A mould is a hollow block which is filled with a liquid like plastic, glass or a rubber. Injection moulding is one of the types of moulding which involves injecting a raw material into a pattern and applying certain factors like heat and pressure.
CYCLE OF INJECTION MOULDING
The sequence of events through which a raw material is converted into a finished part is known as the injection mould cycle. It includes the supply of granules being fed into a hopper to a heated chamber, where the granules are melted into the form of a liquid. Then a plunger is used to force the liquid through a nozzle to the mould. These processes are repeated again to form a cycle for mass production of products.
TYPES OF PLASTIC INJECTION MOULDING
The above described method is the conventional method of plastic injection moulding, although various other unconventional processes include co-injection moulding, fusible core injection method, injection-compression moulding, thin-wall moulding, powder injection moulding and many more.
With Plastic Injection moulding, a variety of plastic goods can be manufactured. Huge numbers of identical products can be manufactured with this process. A design engineer considers lot of parameters and venture specifications and designs accordingly. Manufacturing problems can be prevented right at the initial stage of design itself.
There are more than 30,000 unique products that can be moulded using plastic injection process. Its advantages include repeatable high tolerances, low labour cost, high production rates, easy to finish parts after moulding and the ability to use extensive range of materials. The major advantage of plastic injection moulding is that products with complex geometry can be made which is not possible in any other processes. As long as there is a need for plastic components of complex shapes and sizes, the business of manufacturing plastics will continue to grow.