· Injection mould
Injection mold is also called injection mold. The characteristic of the molding process of this mold is that the plastic raw materials are 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 casting system of the mold, and the plastic is formed by heat preservation, pressure holding, cooling and solidification in the mold cavity. Because the heating and pressing device can function in stages, injection molding can not only form plastic parts with complex shapes, but also have high production efficiency and good quality. Therefore, injection molding occupies a large proportion in the molding of plastic parts, and injection molds account for more than half of plastic molding molds. The injection machine is mainly used for the molding of thermoplastics, and in recent years it has also been gradually used for the molding of thermosetting plastics.
· Compression mold
Compression molds are also called pressing molds or rubber molds. 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 molten under the action of heat and pressure, the cavity is filled with a certain pressure. At this time, the molecular structure of the plastic produces a chemical cross-linking reaction, which gradually hardens and sets. Compression molds are mostly used for thermosetting plastics, and most of the molded plastic parts are used in the shell of electrical switches and daily necessities.
· Transfer mode
The transfer mold is also called compression injection molding or extrusion molding. The molding process of this mold is characterized by adding plastic raw materials into the preheated charging chamber, and then applying pressure to the plastic raw materials in the charging chamber from the pressure column. The plastic melts under high temperature and high pressure and enters the cavity through the mold pouring system Chemical crosslinking occurs and gradually solidifies. The transfer molding process is mostly used for thermosetting plastics, which can form plastic parts with relatively complicated shapes.
· Extrusion die
The extrusion die is also called extruder head. This mold can continuously produce plastics with the same cross-sectional shape, such as plastic pipes, rods, sheets, etc. The device for heating and pressurizing the extruder is the same as the device for the injection machine. The molten plastic passes through the machine head to form continuous molded plastic parts, and the production efficiency is particularly high.
In addition to the plastic molds listed above, there are vacuum forming molds, compressed air molds, blow molding molds, and low-foam plastic molds.