Injection molds are parts that give plastics shape and size during molding. Although the structure of the mold may vary greatly due to different types and properties of plastics, the shape and structure of plastic products, and the type of injection machine, the basic structure is the same.

According to the molding characteristics, injection molds are divided into two types: thermoset plastic molds and thermoplastic plastic molds; according to the molding process, they are divided into plastic transfer molds, blow molds, casting molds, thermoforming molds, hot compression molds (compression molds), injection molds, etc. Among them, the hot press mold can be divided into overflow type, semi-overflow type and non-overflow type by overflow mode, and injection mold can be divided into cold runner mode and hot runner mode by pouring system; according to loading and unloading mode It can be divided into two types: mobile and fixed. The classification of the mold is also distinguished according to the different processing techniques. The injection mold is to inject the molten plastic into the cavity of the mold at a certain speed and pressure. After the plastic is cooled, open the mold to take out the molded injection product.

Compression mold is simply referred to as compression mold. The plastic material is directly added to the open mold cavity, the mold is closed, and the plastic becomes a fluid state and fills the cavity under the action of heating and pressure. Then the product is chemically crosslinked or physically cooled Hardening and setting.

The compression mold uses a heated mold to heat and press the plastic sheet into a shape, then opens the mold, takes out the formed product, and puts it into cold water for cooling. Compression molding is an important technical process in molding processing. It has a wide range of applications in industrial production and industrial processing, and plays an important role in people's lives. Generally, powdery, granular, agglomerated, flake, or even shaped blanks similar to the product are first placed in the cavity of a heated mold, and then the mold is closed and pressurized to form and solidify or vulcanize. The product obtained by demolding is particularly suitable for the molding process of thermosetting plastics (see thermosetting resins). The disadvantages are long production cycle, low efficiency, and poor dimensional accuracy of the product.