Plastic machining, also known as plastic injection molding, is a general term for the process of converting synthetic resin or plastic into plastic products. Addition polymers, the raw materials used plastic machining generally need to add various plastic additives, such as stabilizers, plasticizers, colorants, lubricants, reinforcing agents and fillers, etc, to improve performance or reduce costs after machining. Additives and polymers are mixed and uniformly dispersed into powder, also known as dry mix. Part of the powder it also needs to be plasticized and processed into pellets. This powder and pellets are collectively referred to as batch materials or molding compounds.

Different from metal machining, due to the poor thermal conductivity of plastic, low thermal expansion coefficient and elastic modulus, when the fixture or tool is pressurized too much, it is easy to cause deformation, easy to melt when heated, and easy to adhere to the tool. Therefore, when machining plastics, the tools used and the corresponding cutting speeds must be adapted to the characteristics of plastics. Commonly plastic machining methods include sawing, shearing, punching, turning, planing, drilling, grinding, polishing, threading, etc. In addition, plastics can also be laser cutting, punching and welding.