The machinability and mold life of injection mold have great relationship with the steel

The machinability and plastic injection mold life of injection mold have great relationship with the steel, so the mold steel is very important, generally saying mold steel must have below characteristics.

(1) High wear resistance

In order to improve the rigidity and mechanical property, glass fiber and inorganic filler are variously filled into plastic material use to reinforce the plastic material, they are injected into the mold cavity with the melted plastic in high speed, it causing a great wear to the mold cavity, there for mold steel should have high wear resistance.

(2)High corrosion resistance

 Lots of resin additive such as fire retardant, even the plastic material itself may be corrosive. When the resin material is mixed with filler, it could intensify the damage to the cavity, there for the cavity must apply chroming or nickeling.

(3) High thermo conductive

During the molding process, good temperature control is very important to the quality of the part. Usually copper alloy have better thermo conductive than steel, but it has lower elastic modulus, hardness and wear resistance. The low thermo conductive of steel can be compensate by cooling system.

(4) Good dimension stableness

In the molding process, the cavity temperature can be up to 300℃, great temperature difference can cause thermal expansion and thus cause the unstable of the part dimension, therefor heat-treated and pre-harden steel is preferred for better dimension stableness.

(5) Polishing ability

The surface quality of the plastic part is determined by the cavity surface quality. So the polishing ability of the steel is important for injection mold. The steel must have a good polishing ability and have no defect such as pore.