Compression Moulding

The compression moulding of plastics is broadly similar to the pressing of metals and ceramics. It is used to form thermosetting plastics such as urea-formaldehyde. A measured ammount of the plastic is placed into the mould where it is heated and then compressed into the required form by a punch.
Items such as electric light and power sockets and ash-trays are produced by this process. The surface finish tends to be very good.