The peeling issue will be caused by the poor aluminum casting quality issue, such as the foreign material contamination issue. And if the castings are shot blasted, the anodized surface will be damaged.The anodized surface can not be removed completely,partial oxide layer will still remained on the castings.
The shot blasting is to reduce the porosity in the aluminum casting. Normally, the pressure is about 3 KGf per square centimeters. But the peeling issue will happen easily if there are gas holes, air bubble or cold shut in the casting. This is different from the peeling issue on pressure die casting parts.
For the above issues, there are not effective ways now, but there are some solution suggestions as below:
1. To improve the inner constant quality of the casting parts;
2. Reduce the shot blast strength;
3. Polish the peels, and shot blast the casting again.