Plastic mold is a kind of used for compression molding, extrusion molding, injection, blow molding and low foam molding combined mold abbreviation. The coordinated change of the mold convex, concave and auxiliary molding system can process a series of plastic parts with different shapes and sizes. In order to meet the needs of molding parts, we need to pay attention to some matters when choosing plastic molds, and put forward the corresponding requirements. The following choose a more suitable plastic mold needs to meet the six requirements.

1, high corrosion resistance Many resins and additives have a corrosive effect on the surface of the cavity. This corrosion causes metal corrosion and peeling on the surface of the cavity, the surface condition deteriorates, and the quality of the plastic parts deteriorates. Therefore, it is best to use corrosion-resistant steel, or chrome plating on the surface of the cavity, cymbal nickel treatment.

2. Good wear resistance The gloss and precision of the surface of the plastic part are directly related to the wear resistance of the surface of the plastic mold cavity. Especially when glass fiber, inorganic filler and some pigments are added to some plastics, they flow at high speed in the runner and mold cavity together with the plastic melt, causing great friction to the surface of the mold cavity. If the material is not wear-resistant, it will soon wear and damage the quality of the plastic part.

3, good dimensional stability In plastic molding, the temperature of the plastic mold cavity should reach above 300 ℃. For this reason, it is best to use tool steel (heat-treated steel) that has been properly tempered. Otherwise, it will cause changes in the microstructure of the material, resulting in changes in the size of the plastic mold.

4, easy to process the mold parts are mostly made of metal materials, and some structural shapes are still very complex. In order to shorten the production cycle and improve efficiency, the mold materials are required to be easily processed into the shape and precision required by the drawings.

5, good polishing performance plastic parts are usually required to have a good gloss and surface state, so the cavity surface roughness is very small, so that the cavity surface must be surface processing, such as polishing, grinding and so on. Therefore, the selected steel should not contain rough impurities and pores.

In order to improve the hardness and wear resistance, the plastic mold is generally heat treated, but this treatment should make its size change very small. Therefore, it is preferable to use prehardened steel which can be machined.