Coring

Coring refers to the elimination of plastic material in oversized dimensioned areas by adding steel to the mold tool that usually results in a pocket or opening in the part. For simplicity and economical reasons cores should ideally be placed parallel to the line of draw. Coring designs.
Cores in other directions require the use of some form of side action (cam operated or hydraulic) to be actuated thus increasing tooling costs (see figure below). Constuction B could cost as much as 60% less than A.