The working principle of the plastic injection molding machine is similar to that of the syringe for injection. It is the process of injecting the plasticized plastic in the melt state (i.e. viscous flow state) into the closed mold cavity with the help of the push force of the screw (or plunger), and obtaining the product after curing and shaping. Injection molding is a cycle process, each cycle mainly includes: quantitative feeding - melting and plasticizing - pressure injection - mold filling and cooling - mold opening and parts removal. Take out the plastic parts and then close the mold for the next cycle.