What happened to the blistering of EPS foam products?

First, EPS foam machinery hair material is not uniform, drying time is long, blistered.
Second, if there is no drying, it should be cooling water into less or short cooling time.
Third, EPS foam machinery material is not well developed, there may be light and heavy material mixed together to cause.
Fourth, if into the baking room is likely to be too long baking time.
Fifth, if it is just out of the mold is the problem of material, there is a mix of material, the combination is not the same.
