The cavity is made and the material of the runner is subjected to strict heat treatment. It is necessary to select alloy steel with high mechanical strength, or high hardness (molding parts to reach about HRC52), good wear resistance and strong corrosion resistance.
In the design of the mold structure, the number of cavities should not be too much, and the bottom plate, the support plate and the cavity wall should be thicker to avoid the severe elastic deformation of the parts under high temperature and high pressure.
The mold should try to take a small number of cavities, a small and short flow path and a higher finish than the ordinary mold, which is beneficial to demoulding.
The accuracy of the plastic parts mainly depends on the dimensional accuracy of the mold cavity, the positioning accuracy of the cavity, and the accuracy of the parting surface. The criterion for judging is whether the design of the plastic part is easy to process, whether the filling property of the mold gate is good, whether the cooling system of the mold can uniformly cool the mold, and the like. The dimensional tolerances of general precision injection molds should be controlled below 13 for product dimensional tolerances.