1) Identification of wrong pattern in
Wrong mold is the defect that one part of the casting and another part are staggered at the parting surface, which is generally caused by the inaccuracy of mold closing and positioning.
If there is sand core in the mold, and the sand core is placed in the lower mold, the defect is wrong mold rather than eccentric core.
2) Identification of wrong core in sand casting
The staggered core is that the sand cores are staggered at the core separation surface, which makes the inner cavity of the casting deformed. It is a wrong core, not a wrong mold, so the shape of the outer surface of the casting is correct.
3) Identification of eccentric core in sand casting
The eccentric core is caused by the unexpected change of the position of the sand core, and the shape and size of the casting are inconsistent with the drawing.