Now  i am developing a heat radiation base of LED lamp.The base is a die-casting part which need to painting by powder technology.  but,when it was painted by powder technology and its surface were many air bubbles.as you know,this product is cosmetic.we give many ways to solve this problem in die-casting and painting process.and there is not using at all.who can help me.who can give me some advice.i will be appreciated.