Many problems can arise in the casting production process, such as mold shifting defect. This defect may cause the castings unqualified.
Mold shift is exactly what it sounds like. If the cope and drag of a pattern do not align perfectly, it will produce a defective casting, such as the one pictured right. It is up to the operator to ensure that the cope and drag are aligned perfectly, but there are also ways to help prevent this error.
The most common way to prevent a mold shift is to use some type of alignment pins to ensure the cope and drag align perfectly.
But for those metal casters who are casting at home, making sure the cope and drag are aligned can be tricky and involve a lot of trial and error. Once you produce an accurate casting, mark the cope and drag so that you can align them much easier to produce the next casting. But most importantly just take your time and check twice to pour once.