The molding process of a general screw injection molding machine is as follows: first, granular or powdered plastic is added to the barrel, and the plastic is melted by the rotation of the screw and heating of the outer wall of the barrel. Then, the machine closes the mold and moves the injection seat forward to make the nozzle close to the sprue of the mold. Then, pressure oil is introduced into the injection cylinder to push the screw forward, so that the molten material is injected into a closed mold with a low temperature at a high pressure and a fast speed. After a certain period of time and pressure maintenance (also known as pressure maintenance) and cooling, the plastic is solidified and formed. The mold can be opened and taken out (the purpose of pressure maintenance is to prevent the backflow of molten material in the mold cavity, supplement material to the mold cavity, and ensure that the mold cavity is filled with material, and the mold cavity is formed. The product has a certain density and dimensional tolerance. The basic requirements for injection molding 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, injection must ensure sufficient pressure and speed. At the same time, due to the high injection pressure, a corresponding high pressure is generated in the mold cavity (the average pressure inside the mold cavity is generally between 20 and 45 MPa), so there must be sufficient clamping force. It can be seen from this that the injection device and the clamping device are key components of the injection molding machine.