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русский Injection molding
The plastic is first added to the heating barrel of the injection machine, and the plastic is heated and melted. Under the push of the screw or plunger of the injection machine, it enters the mold cavity through the nozzle and the mold pouring system, and is hardened and shaped into injection molding due to physical and chemical effects. product.
Injection molding consists of a cycle consisting of injection, pressure holding (cooling) and plastic part demolding processes, so injection molding has the characteristics of periodicity. Thermoplastic injection molding has a short molding cycle, high production efficiency, and low wear on the mold by the melt. It can mold plastic parts with complex shapes, clear surface patterns and markings, and high dimensional accuracy in large quantities; however, for plastics with large wall thickness changes. It is difficult to avoid molding defects. Anisotropy of plastic parts is also one of the quality problems, and all possible measures should be taken to minimize it.
Compression molding
Commonly known as compression molding, it is one of the earliest methods of molding plastic parts. Compression molding is to directly add plastic into an open mold cavity with a certain temperature, then close the mold, and melt the plastic into a flowing state under the action of heat and pressure. Due to physical and chemical effects, the plastic is hardened into a plastic part with a certain shape and size that remains unchanged at room temperature.
Compression molding is mainly used for molding thermosetting plastics, such as phenolic molding powder, urea-formaldehyde and melamine-formaldehyde molding powder, glass fiber reinforced phenolic plastic, epoxy resin, DAP resin, silicone resin, polyimide and other molding compounds, It can also be processed into unsaturated polyester dough (DMC), sheet molding compound (SMC), prefabricated integral molding compound (BMC), etc. Under normal circumstances, compression dies are often divided into three types: overflow type, non-overflow type, and semi-overflow type according to the matching structure of the upper and lower molds of the compression film.
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