These six requirements for the purchase of plastic molds cannot be ignored

Time:2020/7/13 11:02:35

　　 Plastic mold is an abbreviation for a combined mold for compression molding, extrusion molding, injection, blow molding and low foam molding. A series of plastic parts with different shapes and different sizes can be processed by the coordinated changes of the mold convex and concave molds and the auxiliary molding system. In order to meet the needs of molded parts, we need to pay attention to some matters when choosing plastic molds, and put forward corresponding needs. The following selection of more suitable plastic molds 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 the metal on the surface of the cavity to be corroded and peeled off, the surface condition is deteriorated, and the quality of the plastic parts is deteriorated. Therefore, it is best to use corrosion-resistant steel, or chrome-plated and cymbal nickel on the surface of the cavity.
　　 2. Good abrasion resistance The gloss and precision of the surface of plastic parts are directly related to the abrasion resistance of the surface of the plastic mold cavity, especially when some fibers are added with glass fiber, inorganic fillers and certain pigments. Together with the plastic melt, it flows fast in the flow channel and the mold cavity, and the friction on the surface of the cavity is very large. If the material is not wear-resistant, it will quickly wear out and damage the quality of the plastic parts.
　　 3. Good dimensional stability During 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 mold parts are mostly made of metal materials, and some structural shapes are also very complex. In order to shorten the production cycle and improve efficiency, mold materials are required to be easily processed into the shape and accuracy required by drawings.
　　 5. Polishing performance Plastic and plastic parts usually require good gloss and surface condition, so the roughness of the cavity surface is very small. In this way, the cavity surface must be surface-processed, such as polishing and grinding. Therefore, the selected steel should not contain rough impurities and pores.
　　 6. Less affected by heat treatment In order to improve the hardness and wear resistance, plastic molds are generally heat treated, but this treatment should make its size change small. Therefore, it is best to use pre-hardened steel that can be cut.