Injection moulding (
injection molding in the USA) is a
manufacturing process for producing parts by injecting material into a mould. Injection moulding can be performed with a host of materials, including metals, (for which the process is called
diecasting),
glasses,
elastomers, confections, and most commonly
thermoplastic and
thermosetting polymers. Material for the part is fed into a heated barrel, mixed, and forced into a mould cavity, where it cools and hardens to the configuration of the cavity. After a product is designed, usually by an
industrial designer or an
engineer, moulds are made by a
mouldmaker (or toolmaker) from
metal, usually either
steel or
aluminum, and
precision-machined to form the features of the desired part. Injection moulding is widely used for manufacturing a variety of parts, from the smallest components to entire
body panels of
cars. Advances in
3D printing technology, using photopolymers which do not melt during the injection moulding of some lower temperature thermoplastics, can be used for some simple injection moulds.