Is a manufacturing process for producing parts from both thermo plastic and thermo setting plastic materials.
Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the mold cavity. 

After a product is designed, usually by an industrial designer or an engineer, molds are made by a mold maker (or toolmaker) from metal, usually either steel or aluminum, 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 component to entire body panels of cars.