Mainly used in thermosetting plastics (see thermosetting resins) molding, such as phenolic, melamine formaldehyde, urea-formaldehyde plastics, and also used to make unsaturated polyester and epoxy resin glass fiber reinforced plastic products. Thermoplastic plastics (see thermoplastic resins) are also molded by this method, such as vinyl vinyl records. But thermoplastic molding, molds must be cooled before the product demoulding, in the next workpiece before molding, and must be heated again, so the production efficiency is very low. Molding method in the rubber industry is also a very important molding methods, plastic material trim or cut into simple shapes, add heating molds, in the molding at the same time vulcanization, products are also hot demoulding. Many rubber model products such as sealing pads, damping products (such as aprons, rubber plates) are produced by this method.
Process: feeding, closing, exhaust, curing, demoulding and mold cleaning, and so on if the products are embedded in the molding need to seal the insertion, then the insertion should be inserted before feeding. The main control process conditions are pressure, mold temperature and molding time. In addition, there is a special form of molding method, which is the first powder plastic compaction, and then remove the material from the mold, put in the furnace heated to the melting point, so that the plastic particles melt into a whole, cooling after the products or semi-finished products. This method is called sintering molding, mainly used in PTFE molding.