Injection molding is a manufacturing process used to produce parts via injecting material into a mold. Injection molding is performed on metals, elastomers, glasses, and the most common, thermoplastic and thermosetting polymers. Material is forced into a heated barrel, forms to fit the cavity, cools, and hardens to the shape of the mold. Recent advances in 3D print technology use photopolymers that do not melt during injection molding of lower temperature thermoplastics for simpler injection molds.

The versatility of injection molding allows for the modification of features, such as the material used for the part, the desired shape and features of the part, the properties of the machine, and the material of the mold. Injection molding is commonly used for detailed Features and Complex Geometry. Due to the amount of pressure needed to complete the mold, injection molding allows for the most detailed designing of separate parts in complex, precise, and intricate shapes that are too complicated and expensive to otherwise manufacture.