The molding process of general screw injection molding machine is: firstly, the granular or powdery plastic is added into the barrel, and the plastic becomes molten through the rotation of the screw and the heating of the barrel outer wall. Then, the machine closes the mold and moves the injection seat forward to make the nozzle close to the gate of the mold. Then, the injection cylinder is filled with pressure oil to make the screw move forward, so that the screw can be pushed forward with high pressure and speed After a certain period of time and pressure holding and cooling, the product can be opened to take out the product.