Most other surface factors are controlled with proper foundry practices. Soundness and Tolerance Soundness of metal components refers to freedom from impurities such as sand inclusions, slag inclusions, macro porosity, and shrinkage. Standard green sand casting practices produce metal castings of sufficient soundness for load-bearing structural applications. At North Star, we offer casting and inspection methods to verify special soundness requirements for any demanding application. Industries such as transportation, power generation, military, and others, all find use for North Star cast parts.
Tolerance refers to the dimensional accuracy achievable for a given production method.
For the green sand casting process, mold expansion, solidification shrinkage, and thermal contraction all influence the tolerance of the finished part. Consequently, there are limits for tolerancing an as-cast part. Subsequent machining is commonly employed when a tighter tolerance is required. As seen from the table, tolerance control increases with price. Not intended for design.