How to identify the quality of lost foam castings?

How do we identify the quality of the lost foam casting? Select the lost foam casting sand, according to the casting material, use and process requirements to choose. EPC entire appearance of each site density must reach consensus. The internal fusion of foam mold of lost foam casting can not be lost. EPC pattern(Expendable Pattern Casting) surface quality must be smooth and clean.These are the key to identify lost foam castings quality.