There are many ways to classify automotive plastic moulds. According to the different methods of forming and processing plastic parts, they can be divided into the following categories:
The characteristic of the plastic injection molding is that the plastic raw material is placed in the heating barrel of the injection molding machine. The plastic is melted by heat, driven by the screw or plunger of the injection molding machine, enters the mold cavity through the nozzle and the pouring system of the mold, and the plastic is formed by heat preservation, pressure retention, and cooling in the mold cavity. Since the heating and pressing device can function in stages, injection molding can not only form plastic parts with complex shapes, but also has high production efficiency and good quality. Therefore, the injection mold occupies more than half of the proportion in the molding of plastic parts. Injection molding machines are mainly used for the molding of thermoplastics, and in recent years have gradually been used for the molding of thermoset plastics.
The characteristic of the molding process of this automotive plastic mould is that the plastic raw material is directly added into the open mold cavity, and then the mold is closed. After the plastic is in a molten state under the action of high temperature and pressure, the cavity is filled with a certain pressure. At this time, the molecular structure of the plastic has a chemical cross-linking reaction, which gradually hardens and sets. Compression molds are mostly used for thermosetting plastics, and their molded plastic parts are mostly used for the shells of electrical switches and daily necessities, such as home appliance mould.
The characteristic of the molding process of this automotive injection mold is that the plastic raw materials are added into the preheated feeding chamber, and then pressure is applied to the plastic raw materials in the feeding chamber by the pressure column. The plastic is melted under high temperature and high pressure and enters the cavity through the casting system of the mold. , And then the chemical cross-linking reaction occurs and gradually solidified into shape. The transfer molding process is mostly used for thermosetting plastics, which can form plastic parts with more complex shapes.
This automotive plastic mould can continuously produce plastics with the same cross-sectional shape, such as plastic pipes, rods, and sheets. The heating and pressurizing device of the extruder is the same as that of the injection molding machine. The plastic in the molten state will form a continuous molded plastic part through the machine head, and the production efficiency is particularly high.
In addition to the several types of plastic molds listed above, automotive plastic mould molding processes include vacuum molding molds, compressed air molds, blow molding molds and low-foaming plastic molds.