Plastic mold common failure form – shrinkage

//Plastic mold common failure form – shrinkage

There exits shrinkage in surface of die cast mold. I will introduce you in details as followings:


Shrinkage hole is the surface of the die cast mold surface or the existence of a surface rough hole. There also are a lot of small shrinkage hole, that is, shrinkage. Shrinkage often occurs in the castings near the runner, riser root, thick parts, the thickness of the wall junction and has a large plane of the thickness.


  1. The temperature control of die cast mold does not meet the directional solidification requirements.
  2. The choice of paint is improper, different parts of the coating layer thickness control is not good.
  3. The casting mold in the position of improper design.
  4. Pouring riser design failed to achieve the full complement from the role.
  5. Pouring temperature is too low or too high.

Control methods:

  1. Improving the abrasive temperature.
  2. Adjusting the thickness of the coating layer and uniforming spray paint, coating off and the coating can not be formed when the local accumulation of paint phenomenon.
  3. The die cast mold is local heated or insulation with local insulation materials.
  4. Hot section at the copper block, while chilling the local.
  5. The mold design heat sink, or through water and other local areas to speed up the cooling rate.
  6. With removable chi-chill cold block, in turn placed in the cavity, to avoid continuous cooling chill itself when the production is not sufficient.
  7. The mold riser design pressure device.
  8. Pouring system design to be accurate, select the appropriate pouring temperature.