Compression moulding

Process:   A measured amount of, usually powdered, material is added to a two-part mould and subjected to heat and pressure.  As the material softens it fills the cavity, it is then cooled within the mould.

Introduced:   Before 1900.

Plastics:   Usually thermosets, especially melamine formaldehyde and phenol formaldehyde with filler.

Marks:   Mould lines, but these can be polished off by hand.

Tooling cost:   Medium.

Production volume:   Relatively slow and labour intensive.

Uses:   Radio and telephone housings; plugs and sockets; tableware; ashtrays; bowls and boxes.