Compression Moulding

Compression moulding is a common process used for both thermoplastic and thermoset stock shape materials. Compression moulding is accomplished by placing the plastic material (can be a granular or pelletised form) in a mould cavity to be formed by heat and pressure. The heat and pressure force the materials into all areas of the mould. The heat and pressure cycle of the process will harden the material and then it can be removed.

Typically, thermosetting compounds like polyesters, phenolics, melamines and other resin systems are compression moulded using alternating layers of different reinforcement materials to create a final product. However, there are various thermoplastics that are commercially compression moulded as well.

Compression moulding is a valuable tool where it has a fit. Obviously for thermosets, it is a primary process but in thermoplastics it can often times be useful in creating a base stock shape to machine extremely complex geometries without having to take excessive time and steps to anneal parts. This can increase production cycle time and reduce overall cost while delivering exceptional finished parts. 

There are a host of advantages when it comes to compression molding. First of all, just for reference, advanced composites in general offer many advantages compared to metal parts, including lighter weight, high strength, high stiffness and corrosion resistance, depending upon the type of composite material.