As we all know, plastic moulds have many requirements for materials, especially for some large mould processing factories, the requirements for materials are even more stringent. So what are the general requirements for plastic moulds for materials? Let's take a look with the mould processing factory!
Surface hardness and wear resistance
The general hardness of plastic moulds is generally below 50-60HRC. The back mould should have sufficient surface hardness to ensure that the mould has sufficient rigidity. Since the injection mould is subjected to pressure and friction during work, it is required to maintain stable shape accuracy and size accuracy of the mould to ensure that the plastic household mould has sufficient service life. The wear resistance of the die head depends on the chemical composition of the steel and the hardness of the alloy. Increasing the hardness of the die head is beneficial to improving its wear resistance.
Most plastic moulds require cutting and fitter repair in addition to EMD processing. The hardness of the mould steel must be appropriate to extend the service life of the cutting tools, improve their performance, and reduce the surface roughness.
Good heat resistance
High-quality plastic products require small surface roughness. For example, the surface roughness value of the injection mould cavity is less than 0.1, and the optical surface requires Ra<0.01 at the level of 0.25, and in order to reduce surface roughness, cavity must be used. The steel used in this product should have less material impurities, fine and uniform organization, no tendency for fiber, and no pitting or orange peel defects.
Good thermal stability
The shape of plastic injection moulding technology parts is often more complicated. After quenching, it is difficult to process. It should be processed as much as possible with injection moulds that have good thermal stability. Due to the small linear expansion coefficient, small deformation, small change in size, stable metallographic structure and mould size, machining can be reduced or stopped, which can ensure the required mould size accuracy and surface roughness.
The dynamic mould is installed on the moving mould of the injection moulding machine, and the fixed mould is installed on the fixed plate of the injection moulding machine. During the injection moulding process, the closing of the dynamic mould and the fixed mould constitute the pouring system and the mould cavity. When opening the mould, the dynamic mould and the fixed mould are separated to take out the plastic products. Although the structure of the mould will change due to the different types and performance of plastic household moulds, the shape and structure of plastic products, and the type of injector, the basic structure is the same. The mould is mainly composed of pouring system, temperature control system, moulding parts and structural parts. In the plastic mould, the pouring system and the moulded parts are the parts that are directly in contact with the plastic, and are the most complex, variable and require the highest processing smoothness and accuracy.
Injection moulds are tools for manufacturing plastic moulds and also tools for giving plastic products complete structures and precise dimensions. Injection moulding is a processing method used to mass-produce specific-shaped complex parts. Specifically, it refers to the process of injecting the heated and melted plastic into the mould cavity under high pressure through the injection moulding machine, cooling and solidifying to obtain the moulded product.