The injection mold consists of two parts: a movable mold and a fixed mold. The movable mold is mounted on the moving template of the injection molding machine, and the fixed mold is mounted on the fixed template of the injection molding machine. In the injection molding, the movable mold and the fixed mold close constitute a casting system and a cavity, and when the mold is opened, the movable mold and the fixed mold are separated to take out the plastic product.

Although the structure of the mold may vary depending on the type and performance of the plastic, the shape and structure of the plastic product, and the type of the injection machine, the basic structure is uniform. The mold is mainly composed of a gating system, a temperature control system, a molded part and a structural part. The gating system and the molded part are in direct contact with the plastic and vary with the plastic and the product. It is the most complicated and most varied part of the mold, and requires the highest degree of smoothness and precision.

The gating system refers to the part of the flow path before the plastic enters the cavity from the nozzle, including the main channel, the cold material hole, the shunt channel and the gate. Molded parts refer to various parts that make up the shape of the product, including moving molds, fixed molds and cavities, cores, forming rods, and exhaust ports.