The most important part of the automobile plastic mold is the cover mold. This type of die is mainly a cold die. In a broad sense, “automobile mold” is the general term for the molds used to manufacture all parts of automobiles. For example, stamping molds, injection molds, forging molds, casting wax molds, glass molds, etc.
There are many ways to classify automobile plastic molds. According to the different methods of molding and processing plastic parts, they can be divided into the following categories:
Injection mold is also called injection mold. The molding process feature of this mold is that the plastic raw material is placed in the heating barrel of the injection machine. The plastic is melted by heat, driven by the screw or plunger of the injection 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. Because the heating and pressurizing device can function in stages, injection molding can not only mold plastic parts with complex shapes, but also has high production efficiency and good quality. Therefore, injection molding occupies a large proportion in the molding of plastic machining parts, and injection molds account for more than half of plastic molding molds. Injection machines are mainly used for the molding of thermoplastics, and in recent years have gradually been used for the molding of thermoset plastics.
Compression mold is also called compression mold or compression mold. The molding process of this mold is characterized by adding plastic raw materials directly into the open mold cavity and then closing the mold. After the plastic is in a molten state under the action of heat 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.
Transfer mold is also called injection mold or extrusion mold. The molding process of this mold is characterized by adding plastic raw materials 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. The chemical cross-linking reaction occurs and gradually solidifies and forms. The transfer molding process is mostly used for thermosetting plastics, which can form plastic parts with more complex shapes.
The extrusion die is also called the extrusion head. This kind of mold can continuously produce plastics with the same cross-sectional shape, such as plastic pipes, rods, and sheets. The heating and pressing device of the extruder is the same as that of the injection machine. The molten plastic 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, there are vacuum molding molds, compressed air molds, blow molding molds, low-foaming plastic molds, etc.