The Relationship between Injection Mold Material and Mold Life
The durability of the injection mold is very important to the material used. Therefore, it is necessary to pay attention to the selection of the mold material. Generally, the mold material should have the following properties:
(1) high wear resistance
In order to increase the rigidity and mechanical properties of plastic parts, in the plastic formula widely used glass fiber, inorganic filler to enhance the addition of these additives, they melt together with the melt into the mold cavity, the mold cavity friction , If the mold material is not wear, it is easy to make the cavity by excessive wear and tear, therefore, the production of such mold materials should have better wear resistance.
(2) high corrosion resistance
Many plastic additives, such as flame retardants, etc., and even the chemical action of the melt itself will corrode the mold cavity. When the plastic raw materials mixed with abrasive filler and reinforcing materials, it is easier to exacerbate the mold damage, which is best to use corrosion-resistant steel, or the surface of the mold plating, chrome or nickel.
(3) good thermal conductivity
In the injection molding, good mold temperature control on the quality of plastic parts a great impact, especially in the processing of semi-crystalline thermoplastic is even more important. In general, copper alloys are much more thermally conductive than alloy steels, but have low elastic modulus, hardness and durability. Insufficient thermal conductivity of the steel can be compensated by the cooling system.
(4) good dimensional stability
Injection molding mold in the molding operation, the mold cavity temperature to reach more than 300 ℃, the temperature difference is so large, easy to make micro-cavity structure changes, resulting in mold size changes, making the plastic parts size instability, Tempered tool steel, ie heat treated steel. In order to improve the hardness and wear resistance, the mold should be heat treatment. However, this heat treatment should minimize the size of the mold, can be used to cut the pre-hardened steel, the steel in the mechanical processing without heat treatment.
(5) good polishing performance
Mold cavity wall requirements are high, roughness is very small, to meet the requirements of good plastic surface gloss, which, the mold cavity generally to be polished, the surface the more bright the better, for this, the mold material is easy Polished, the selected material should not be caught with impurities and pores and other defects.