A plastic mold is a tool for producing plastic products; it is also a tool for imparting complete structure and precise dimensions to plastic products. The final plastic product is obtained by injection molding plastic raw materials and plastic molds in an injection molding machine. What are the commonly used plastic raw materials in plastic mold factories?
The plastic we often talk about is usually a general term. Generally, plastic raw materials are divided into general plastics and engineering plastics according to their purposes. The plastic raw materials commonly used in plastic mold factories generally include ABS, PP, PVC, PC. These materials are favored by most manufacturers because they have some prominent commonalities, mainly in the following aspects:
1. Easy to process Injection mold parts are mostly made of metal materials, and some structural shapes are very complex. In order to shorten the production cycle and improve efficiency, the mold materials are required to be easy to process into the shape and accuracy required by the drawings.
2. High mechanical strength, strong impact resistance, will not drop rapidly at low temperature; good notch sensitivity, good creep resistance, will not drop rapidly when the temperature rises; have a certain surface hardness, scratch resistance ; Good wear resistance and low friction coefficient.
3. Good wear resistance The gloss and precision of the surface of the plastic parts are directly related to the wear resistance of the surface of the mold cavity, especially when glass fibers, inorganic fillers and some pigments are added to some plastics, they are not related to the plastics. The melt flows at a high speed in the runner and the cavity together, and the friction on the surface of the cavity is very large. If the material is not wear-resistant, it will soon wear out, which will damage the quality of the plastic parts.
4. Good electrical performance, less affected by temperature, humidity and frequency changes.
5. 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 corrode, peel off, deteriorate the surface condition, and deteriorate the quality of the plastic parts. Therefore, it is best to use corrosion-resistant steel, or to chrome-plated or cymbal-nickel on the cavity surface.
6. Low temperature resistance up to -40 degrees Celsius, acid, alkali, salt, oil, water.
7. Good dimensional stability During injection molding, the temperature of the injection mold cavity should reach above 300 °C. For this reason, it is best to choose 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 dimensions of the mold.
8. Smaller shrinkage rate and wider molding process range; surface processing of products can be carried out by coating, printing, electroplating and other methods.
9. Less affected by heat treatment In order to improve the hardness and wear resistance, the mold is generally heat treated, but this treatment should make the size change very small. Therefore, it is best to use pre-hardened steel that can be machined.
10. Good polishing performance Plastic parts usually require good gloss and surface state, so the roughness of the cavity surface is required to be very small. In this way, the surface of the cavity must be subjected to surface processing, such as polishing, grinding, etc. Therefore, the selected steel should not contain rough impurities and pores.
With the continuous development of domestic plastic technology in recent years, the plastic molding process has been continuously improved. It is believed that in the near future, plastic injection molding plastic products from plastic molds will be more widely used in all walks of life.
Post time: Jul-21-2022