Durable degree in injection mold and its relationship with material greatly, therefore must pay attention to material selection, mold material in general, mold material should have the following properties.
  1.high wear resistance. In order to increase the plastic parts of the rigidity and mechanical properties, glass fiber is widely used in plastic formulations, inorganic filler to improve, after adding these additives, melt them with high speed into the mold cavity, the mold cavity friction greatly, if the mold material not wear-resisting, easy to cause the cavity subjected to excessive wear, therefore, making this kind of mold material should have good wear resistance.
  2.high corrosion resistance. Many plastics additives, such as flame retardants, and even melt chemistry itself will erode the mold cavity. When the plastic raw materials mixed with filler containing abrasive and reinforcing material, more easy to aggravate the mold damage, therefore, the best use of corrosion resistant steel, or surface processing of mould, chrome or nickel plated.
  3.Thermal conductivity of good. In injection molding, mold temperature control good has great influence on the quality of plastic parts, especially more significant in the processing of semi crystalline thermoplastic plastics. Usually, the copper alloy is better than the thermal conductivity of the alloy is much, but its elastic modulus, hardness and durability is low. Thermal conductivity of steel can be insufficient cooling system to compensate.
  4.good dimensional stability. In the forming operation of injection mold, the mold cavity temperatures up to 300 degrees, the temperature difference so big, easy to produce changes in the micro cavity structure, causing the mould size change, makes the molding size is not stable, therefore, can be made of tool steel tempering treatment, heat treatment of steel. In order to improve the hardness and wear resistance, generally for the mold to heat treatment. But should make this heat treatment effect on the die size minimum, can use the pre hardened steel cutting processing, this kind of steel without heat treatment after machining.
  5.A polishing performance.. The mold cavity wall is high, very small roughness, in order to adapt to the requirements of good surface gloss of plastic parts, therefore, to the mold cavity is generally applied to the polishing treatment, the surface is bright and better, therefore, requirement of die material is easy to polishing, the selected material should not be clamped with impurities and defects such as pores.