Using volume morphing to compensate shape distortions associated with injection molding

Manufacturing processes often produce parts with shapes that are distorted from the shapes specified in the CAD models created by designers. Volume morphing, a technique pioneered by Pierre Bézier in 1978 and by Sederberg and Parry in 1986, has been used quite successfully to alter tool-surface designs in order to compensate for shape distortions in manufacturing. FESHAPE, a computer software package created at the General Motors Research and Development Center, automatically modifies CAD models according to a finite set of displacement vectors. This article describes the basic methods of FESHAPE and their application to correct distortions produced by thermal stresses during injection molding.