Shell moulding is an expendable mold casting process that uses a resin covered sand to form the mold.
the most preferred process for casting gas turbine blades is Shell moulding.

Shift refers to a defect caused by a sidewise displacement of the mold cope relative to the drag, the result of which is a step in the cast product at the parting line.
Shift is a casting defect which Results in a mismatching of the top and bottom parts of a casting.

Swell is the enlargement of the mold cavity because of the molten metal pressure, which results in localized or overall enlargement of the casting.

Sand wash is a casting defect which Occurs near the ingates as rough lumps on the surface of a casting.