What Is Shrinkage Allowance?

It is defined in DIN EN 12890 and specifies the difference in length of cast parts between casting mold and casting. Only linear shrinkage is taken into account. It depends on the type of casting material, construction as well as the stability of the mold during solidification and shrinkage.

Why is shrinkage allowance provided?

Shrinkage allowance on pattern is provided to compensate for shrinkage when. the temperature of liquid metal drops from pouring to freezing temperature. the metal changes from liquid to solid state at freezing temperature. the temperature of solid phase drops from freezing to room temperature.

How do I calculate shrinkage allowance?

Subtract the final size from the original size to find the amount of the shrinkage. For example, if a felt square shrinks from 8 square inches to 6 square inches, subtract 6 from 8, resulting in 2 square inches of shrinkage.