The structure of the injection mold is determined by the form of the injection machine and the complexity of the parts. During injection, the moving mold and the fixed mold are closed to form the cavity and the casting system, and when the mold opens, the two molds are separated and the plastic parts are taken out. According to the role of each part on the mold, the structure of the injection mold can be divided into:
- Forming parts
Molding parts are specified in the mold, moving parts of the cavity parts, usually by the punch (or core), die, inserts, etc.
- Casting system
The pouring system is the channel through which the molten plastic enters the mold cavity from the nozzle of the injection molding machine.
- Steering mechanism
The guide mechanism is divided into the guide mechanism between the moving die and the fixed die and the guide mechanism of the ejection mechanism. The former is to ensure that the dynamic mold and fixed mold are in the mold to ensure the accuracy of the shape and size of plastic parts.
- Demoulding mechanism
A device for ejecting plastic parts from a mold during mold opening, also known as an ejection mechanism. There are many kinds of structures, such as ejector rod ejector, ejector plate ejector, and ejector tube ejector.
- Lateral parting and core pulling structure
When plastic parts are on the side of a concave or convex shape hole or boss, it is necessary to have a side punch or core to shape. The side punch or side core must be removed from the plastic part before the plastic part can be removed smoothly. The structure which makes the side punch or side core move is called side core-pulling.
- Heating and cooling systems
In order to meet the mold temperature requirements of the injection molding process, the mold temperature must be controlled, so the mold is often equipped with a cooling system and installed in the mold or around the heating elements. The cooling system usually opens a cooling channel on the mold.
- Exhaust system
In the process of injection molding, in order to exhaust the air in the mold cavity, often need to set up the exhaust system, usually in the parting surface to open a number of grooves or use the push rod of the mold or mold core and template with clearance for exhaust. Small plastic exhaust is not large, so you can directly use the parting surface exhaust and do not have to set another exhaust slot.
- Other parts
Such as used to fix, support forming parts or parts for positioning and limited role.
In a word, although the structure of the mold varies with the type and performance of the plastic, the shape and structure of the plastic products, and the type of injection machine, their basic structure is the same. The mold is mainly composed of a pouring system, temperature-regulating system, forming parts, and structural parts. Among them, the casting system and molding parts are the parts in direct contact with plastics and change with plastics and products. It is the most complex part of the plastic mold, with the biggest change and the highest processing finish and precision required.