The injection molding working principle of zipper machinery is a cyclic process, each cycle mainly includes: quantitative feeding - melting plasticization - pressure injection - mold filling cooling - mold opening and pulling. Pull out the plastic part and then close the mold for the next cycle.

The operation items of zipper machinery include three aspects: keyboard operation, electrical control system operation, and hydraulic system operation. Select the injection process action, feeding action, injection pressure, injection speed, and ejection type separately, monitor the temperature of each section of the material barrel, and adjust the injection pressure and back pressure.

The forming process of a general screw type zipper machine is: first, granular or powdered plastic is added to the barrel, and the plastic is melted through the rotation of the screw and the heating of the outer wall of the barrel.

Then, the zipper mechanism closes the mold and moves the injection seat forward to make the nozzle close to the gate of the mold. Then, pressure oil is injected into the injection cylinder to push the screw forward, injecting the molten material into the closed mold at a lower temperature with high pressure and fast speed.

After a certain period of time and pressure maintenance (also known as pressure maintenance) and cooling by the zipper machinery, the product can be solidified and taken out of the mold. The purpose of the zipper machinery's pressure maintenance is to prevent the reverse flow of the molten material in the mold cavity from replenishing the material into the mold cavity, and to ensure that the product has a certain density and dimensional tolerance.

The basic requirements for the working steps of mechanical injection molding of zippers are plasticization, injection, and molding. Plasticization is a prerequisite for achieving and ensuring the quality of molded products, and to meet the requirements of molding, sufficient pressure and speed must be ensured during mechanical injection molding of zippers.