Appearance inspection: There are net-like hair-like protrusions depressions on the surface of the die-casting parts, which will continue to expand extend as the number of die-cast parts increases.

The reasons are as follows:

1) There are cracks on the surface of the die-casting cavity

2) Uneven preheating of die casting mold

The solutions prevention methods are:

1) Die-casting molds should be processed regularly after a certain number of times of die-casting, which should be treated continuously to eliminate the stress in the cavity

2) If cracks have appeared on the surface of the cavity, the molding surface should be polished to remove the crack layer

3) Preheat the mold evenly