Due to the limitation of the present technology level, there are always defects in the die casting, which can not be completely eliminated for the time being, so we can only say that we can minimize the occurrence of bad die casting.
This paper introduces the common die casting defects - flow marks.
Flow mark, also known as stripe, is a relatively easy defect of die casting. The surface of die casting is consistent with the flow direction of liquid metal, and the local sagging smooth pattern can be felt by hand. This defect has no tendency to develop seriously, and the flow mark of die casting can be removed by polishing.
Cause analysis of die casting flow mark:
1. The marks left by two streams of metal that are not filled synchronously.
2. The mold temperature is low, for example, the temperature of zinc alloy die casting mold is lower than 150 ℃. Such defects are easy to occur when the die temperature of aluminum alloy die casting die is lower than 180 ℃.
3. The filling speed is too high.
4. Too much paint.
How to avoid flow mark defects in die casting:
1. Adjust the cross-sectional area or position of the inner gate.
2. Adjust the temperature of die casting die and increase the overflow groove.
3. Adjust the filling speed to change the flow pattern of the cavity filled with liquid metal.
4. The coating shall be thin and evenly sprayed.