Compression moulding is a method of rubber moulding in which the moulding material is first placed in an open, heated mould cavity. The mould is closed and pressure is applied to force the material into contact with the mould areas, whilst heat and pressure are maintained until the mould area has cured. The advantage of compression moulding is its ability to mould large, fairly intricate parts.
Compression moulding was first developed to manufacture composite parts for metal replacement applications; compression moulding is typically used to make large flat or moderately curved parts.
The material to be moulded is positioned in the mould cavity and the heated platens are closed by a hydraulic ram. Sheet mould compound (SMC), is conformed to the mould form by the applied pressure and heated until the curing reaction occurs SMC feed material usually cut to conform to the surface area of the mould. Material may be loaded into the mould in form of pellets or sheet. The material is heated above melting point and formed. The more evenly the feed material is distributed over the mould surface, the less flow orientation occurs during the compression stage