MANUFACTURE OF PLASTIC COMPONENTS FOR AUTOMOBILE BODIES
Amidst increasing fuel prices and its impact on the environment, electric vehicles are finding a permanent spot in every garages these days. While advances are being made every day in terms of battery and motor performances in these vehicles, as a mechanical design engineer, one can start looking for suitable materials for the manufacture of vehicle bodies. While traditional steel and aluminium structures are being replaced by plastics, the manufacturing process for the same is a topic worth mentioning. Let us take a look at one of the most widely used manufacturing process for a typical thermoplastic component: Injection Moulding.
Injection moulding is the most widely used process for the high-volume production of relatively complex thermoplastic parts. In this process, plastic material is melted and injected into a mould to create a part. Once this part cools, the mould opens, and the part drops out.
Granules of raw material are fed by gravity from a hopper into a cavity that lies ahead of a moving plunger. As the plunger advances, the material is forced through a preheating chamber and on through a torpedo section, where it is mixed, melted, and superheated. The superheated material is then driven through a nozzle that seats against a mould. Sprues and runners then channel the molten material into one or more closed-die cavities. Because the dies remain cool, the plastic solidifies almost as soon as the mould is filled. The mould halves must clamp tightly together during moulding and then be easily separated for part ejection.
Injection moulding is an established process for many exterior automotive components, including fenders, grilles, bumpers, door panels, floor rails, light housings, etc. Other applications include instrumentation components, interior surfaces, dashboard faceplates, door handles, glove compartments, air vents etc.
NOTE: Hand drawing sketch of the injection moulding process has been attached along with this write up.