COMPRESSION MOULDING

DESCRIPTION

Compound or blend is placed in mould and heated under pressure. When reaction is complete, product is cooled and ejected.

APPLICATIONS

Electrical switch and fuse boxes. Domestic electrical equipment microwave containers and tableware. Business machine housings. Gas and electricity meter housing. Dish aerials.

NOTABLE POINTS

Original process for 'Bakelite'. Slow process and wasteful for 'flash'. Whilst moulds are simpler than for injection moulding, they must still be made from tool steel.

INJECTION MOULDING

DESCRIPTION

Basically the process used for thermoplastics, modified to avoid hardening of the plastic in the machine.

APPLICATIONS

Electrical switch and fuse boxes. Domestic electrical equipment microwave containers and tableware. Business machine housings. Gas and electricity meter housing. Dish aerials.

NOTABLE POINTS

Can produce more accurate mouldings with better control on material usage. More suited to longer runs.

PRESS MOULDING

DESCRIPTION

Material is charged to a large press with flat platens, generally in the form of a 'pre-preg'. Heat and pressure are applied to react the mixture and convert it into the finished plastic.

APPLICATIONS

Large mouldings. Some sheet products.

NOTABLE POINTS

As with compression moulding, a rather slow process.