Injection molding machine is also called injection molding machine or injection molding machine. It is the main molding equipment for making thermoplastic or thermosetting plastics into plastic products of various shapes by using plastic molding dies. Divided into vertical, horizontal and all-electric type. The injection molding machine can heat the plastic and apply high pressure to the molten plastic so that it can be ejected to fill the mold cavity. Injection system is one of the most important parts of injection molding machine, which generally has three main forms: plunger injection, screw injection and screw preform plunger injection. The most widely used is the screw. Its function is to heat and plasticize a certain amount of plastic in a cycle of injection molding machine within a specified time, and then inject the molten plastic into the mold cavity through the screw at a certain pressure and speed. After injection, the molten material injected into the mold cavity remains fixed.