The six requirements of plastic mould selection and purchase can not be ignored

發(fā)布時間：2019-05-13 The plastic mold is an abbreviation for a combined mold for compression molding, extrusion molding, injection molding, blow molding and low foam molding. The coordinated changes of the mold convex and concave molds and the auxiliary forming system can process a series of plastic parts of different shapes and sizes. In order to meet the needs of molded parts, we need to pay attention to some matters when selecting plastic molds, and put forward corresponding requirements. The choice of a more suitable plastic mold below needs to meet the six requirements.
1. High corrosion resistance Many resins and additives have corrosive effects on the surface of the cavity. This corrosion causes the surface of the cavity to corrode, peel off, the surface condition deteriorates, and the quality of the plastic part Getting worse. Therefore, it is best to use corrosion-resistant steel or chrome-plated, nickel-plated surfaces on the cavity surface.
2, good wear resistance The gloss and precision of the surface of plastic parts are directly related to the wear resistance of the surface of plastic mold cavity, especially some plastics add glass When fiber, inorganic filler and some pigments, they flow with the plastic melt in the flow channel and the cavity, and the friction on the surface of the cavity is very large. If the material is not wear-resistant, it will wear quickly and make plastic The quality of the piece is damaged.
3. Good dimensional stability When molding plastic, the temperature of the plastic mold cavity should reach 300 °C or above. For this reason, it is preferable to use a suitably tempered tool steel (heat treated steel). Otherwise, it will cause a change in the microstructure of the material, resulting in a change in the size of the plastic mold.
4, easy to process mold parts are mostly made of metal materials, and some structural shapes are still very complex, in order to shorten the production cycle, improve efficiency, mold materials are required to be easily processed into drawings Shape and precision.
5, good polishing performance Plastic parts usually require good gloss and surface condition, so the surface roughness of the cavity is required to be very small, so the surface of the cavity must be surface processed Such as polishing, grinding, etc. Therefore, the selected steel should not contain rough impurities and pores.
6. Small heat treatment effect In order to improve hardness and wear resistance, plastic molds are generally heat treated, but this Processing should be such that the dimensional change is small. Therefore, it is preferable to use a pre-hardenable steel that can be machined.