It is divided into feeding, mold closing, exhausting, solidifying, demoulding and mold cleaning. If the inserts of the products need to be sealed during molding, the inserts should be placed before feeding. The main controlled process conditions are pressure, mold temperature and molding time. In addition, there is a special form of molding method, that is, the powdered plastic is first compacted, and then the preform is taken out from the mold, heated in a furnace to a melting point, and the plastic particles are melted into a whole, and the product or semi-finished product is cooled. . This method is called sintering molding and is mainly used for the molding of polytetrafluoroethylene.