Irregular crevices, fissures or voids (apparent or not); usually on the surface of the casting or in the gating
Indicates poor feeding during metal solidification in certain areas
Metal shrinks as it solidifies and the defect occurs if molten metal can’t feed the solidifying area
Causes of this defect are evident in the metal and other portions of the process; to cure, R&R recommends taking the following actions:
Metal temperature is uncontrolled.
Determine optimum temperature and control.
Improper setup to feed casting.
Increase gate size, increase runner size, increase heat pressure. Improve the runner or gating system by enlarging in-gates to allow for metal to enter a part more quickly. Increase the cooling speed of the metal. Reduce the mold mass.
Fill mold quickly.
Rapid or uncontrolled cooling.
Kaowool wrap molds or other external measures.