Injection molding is a manufacturing process for producing parts by injecting molten material into a mold, or mold. Injection molding can be performed with a host of materials mainly including metals, glasses, elastomers, confections, and most commonly thermoplastic and thermo setting polymers.
Material for the part is fed into a heated barrel, mixed, and injected into a mold 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, molds are made by a mold-maker from metal, usually either steel or aluminium, and precision-machined to form the features of the desired part.
Injection molding 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 photo polymers that do not melt during the injection molding of some lower temperature thermoplastics, can be used for some simple injection molds.