There are many ways to classify automotive plastic moulds, according to the different methods of plastic parts forming and processing, they can be divided into the following categories.
1 – Injection mold
The molding process of injection mold is characterized by placing the plastic material in the heated barrel of the injection machine. The plastic is heated and molten, pushed by the injection machine’s screw or plunger, and enters the mold cavity through the nozzle and the mold’s pouring system, and the plastic is cured in the mold cavity through heat preservation, pressure retention, and cooling. Since the heating and pressurizing device can function in stages, injection molding can not only shape complex plastic parts, but also have high production efficiency and good quality. Therefore, injection molding occupies a large proportion in plastic parts molding, and injection molds account for more than half of plastic molding molds. The injection molding machine is mainly used for the molding of thermoplastics, but in recent years it is also gradually used for the molding of thermosetting plastics.
Compression molds are also called pressed rubber molds. The molding process of this mold is characterized by adding plastic raw materials directly into the open mold cavity, then closing the mold, after the plastic is molten under the action of heat and pressure, it fills the cavity with certain pressure. At this time, the molecular structure of the plastic produces a chemical cross-linking reaction, and gradually hardens and sets the shape. Compression mold is mostly used for thermosetting plastics, and its molded plastic parts are mostly used for the shell of electrical switches and daily necessities.
Transfer mold is also called extrusion mold. The molding process of this mold is characterized by adding plastic materials into the preheated filling chamber, and then applying pressure to the plastic materials in the filling chamber by the pressure column, the plastic melts under high temperature and pressure and enters the cavity through the pouring system of the mold, and then chemical cross-linking occurs and gradually cures. The transfer molding process is mostly used for thermosetting plastics and can mold plastic parts with complex shapes.
4 – Extrusion Die
Extrusion die is also called extrusion head. This die can continuously produce plastics with the same cross-sectional shape, such as plastic pipes, rods, sheets, etc. The extruder is heated and pressurized by the same device as the injection machine. The plastic in the molten state passes through the head to form a continuous flow of molded plastic parts, and the production efficiency is particularly high.
In addition to the above listed types of plastic molds, there are also vacuum molding molds, compressed air molds, blow molding molds, low foaming plastic molds, etc.
Post time: Sep-07-2022