Plastic injection molding is a manufacturing process that uses molds to form plastic parts. Various types of plastics when heated can be injected into a mold.
The mass production requirements for plastic or polymer parts in World War II resulted in an improvement on the first injection-molding machine created by Alexander Parker in 1851.
Injection molded plastic is a variety of parts from very small components to parts the size of a body panel of a car. A mold cavity is made from steel or aluminum in precisely the shape of the desired part.