Views: 36 Author: Site Editor Publish Time: 2021-08-30 Origin: Site
The main function of custom plastic injection molds requires plastic film molding. The quality of injection molding tooling has an obvious role in ensuring product quality. Different types of plastic products and the molding process of different products have different requirements for the materials, functions, and shapes of injection molding tooling. With the emergence of high-speed molding machinery, the production of plastic products has accelerated with heat resistance. Because the molding temperature is generally between 160 and 350 ℃, some of the fluidity is not good, and the forming speed is fast, which will cause the molding surface temperature of the mold part to exceed 400 ℃ in a very short time. When the working temperature of the mold is high, the hardness and strength of the mold will decrease, leading to early wear of the mold or plastic deformation and failure. In order to ensure the precision and small deformation of the mold during use, the mold steel should have a higher heat resistance function. In order to reduce the temperature rise, the die steel should have excellent thermal conductivity and a low coefficient of thermal expansion.
The working conditions of the mold with sufficient temperature at the working temperature are mostly very bad, and some often bear a large load, and then cause brittle fracture. The extrusion molding pressure is relatively high, generally 10~35MPa. Therefore, in order to avoid sudden brittle fracture of mold parts during work, custom plastic injection molds must have high strength and toughness. Abrasion resistance follows the expansion of the usefulness of plastic products. In plastic products, it is often necessary to add inorganic materials such as glass fiber to enhance the plasticity. Because the addition of additives greatly reduces the fluidity of the plastic and causes the wear of the mold, the mold is required Has outstanding abrasion resistance. Corrosion resistance Adding flame retardant and polyvinyl chloride to the ABS resin may release corrosive gas during the molding process, and sometimes rust and damage the mold at the mouth of the air flow channel. Therefore, the mold steel is required to have excellent corrosion resistance.
Outstanding cutting functions follow the large-scale, complicated and precise shapes of plastic products, which require the injection molding tooling steel to have outstanding cutting functions and less work hardening during the cutting process. In order to avoid mold deformation and affect accuracy, it is hoped that the residual stress of machining can be controlled to a minimum. Mirror polishing processability The inner and outer surfaces of the mold cavity are lubricated, and the molding surface needs to be polished into a mirror surface, and the surface roughness is lower than Ra0.4μm to ensure the appearance of the plastic molded part and facilitate demolding. Dimensional precision mold inserts have high machining precision and high matching precision. The cavity dimension precision is generally 3~5. The joint surface of the mosaic cavity is required to be tightly closed to prevent the molten material from entering the gap and causing material leakage. Strip pattern photo-etching function Many plastic products add streaks to their appearance in order to beautify. In the leather industry, large-scale leather embossed plates are used, which requires custom plastic injection molds steel to have good photo-etching properties.