Thermoplastic injection molding is the process of melting a plastic material and then injecting it into the membrane cavity. Once the molten plastic enters the mold, it is shaped into a shape by the cold cavity. The resulting shape is often the final product and no further processing is required prior to installation or use as a final product. Many details, such as bosses, ribs, threads, can be formed in one injection molding operation. Injection molding machines have two basic components: an injection device and a clamping device for melting and feeding plastic into the mold. The function of the mold device is: 1. The mold is closed while receiving the injection pressure; 2. The product is taken out of the injection device and melted before the plastic is injected into the mold, and then the pressure and speed are controlled to inject the melt into the mold. There are two types of injection devices currently in use: a screw pre-plasticizer or a two-stage device, and a reciprocating screw.