1、 Definition of injection mold
The mold used for plastic injection molding is called injection molding mold, or injection mold for short. The injection mold can shape plastic products with complex shape, precise size or inserts at one time.
“Seven parts mold, three parts process”. For injection molding, the mold and injection molding machine have a great impact on the quality of molded products, and it can even be said that the mold plays a greater role than the injection molding machine; In injection molding, if the mold is not fully understood, it is difficult to get good molded products.
2、 Structure of injection mold
The structure of injection mold is determined by the type of injection molding machine and the structural characteristics of plastic parts. Each pair of mold is composed of moving mold and fixed mold. The moving mold is installed on the moving plate of the injection molding machine, while the fixed mold is installed on the fixed plate of the injection molding machine; During injection molding, the feeding system and cavity are formed after the moving mold and the fixed mold are closed. When the mold is separated, the plastic part or the beer part is left at the side of the moving mold, and then the plastic part is ejected by the demoulding mechanism set in the moving mold. According to the different functions of each component in the mold, a set of injection mold can be divided into the following parts:
1. Formed parts
The parts that give shape, structure and size to the molding materials are usually composed of core (punch), cavity of concave mold, thread core, insert, etc.
2. Gating system
It is the channel that leads the molten plastic from the injector nozzle to the closed mold cavity. It is usually composed of the main runner, the splitter, the gate and the cold charging well.
3. Guide components
In order to ensure the accurate alignment of the moving die and the fixed die when they are closed, the guide component is set to guide and position. It is composed of guide pillar and guide sleeve. Some molds are also set with guide components on the ejector plate to ensure the smooth and reliable movement of the demoulding mechanism.
4. Demoulding mechanism
Devices for demoulding plastic parts and gating systems have many structural forms. The most commonly used demoulding mechanisms are ejector pin, pipe jacking, roof and pneumatic ejection, which are generally composed of ejector rod, reset rod, slingshot, ejector rod fixing plate, roof (top ring) and roof guide post/sleeve.
5. Mold temperature regulating system
In order to meet the requirements of the injection molding process on the mold temperature, a mold temperature regulating system heating rod is required to adjust the mold temperature.
6. Exhaust system
In order to discharge the gas in the mold cavity smoothly, an exhaust slot is often set at the mold parting surface and the fitting place of the insert.
8. Other structural parts
It refers to the parts set to meet the requirements of mold structure (such as fixed plate, movable/fixed template, support column, support plate and connecting screw)