Shrinkage and Warpage

Plastic part designers often use design for manufacturing and assembly (DFMA) guidelines to reduce the number of parts in an assembly [1]. For this reason, plastic part designs can be extremely complex with many features and tight tolerances. The delivery of plastic moldings that satisfy the dimensional requirements is a joint responsibility of the mold designer, molder, material supplier, and part designer. The part designer should provide a design with uniform thicknesses and achievable specifications. The material supplier should provide consistent polymer resin and useful guidance regarding material properties. The molder should select suitable and consistent processing conditions for operation of the mold. The mold designer should provide a mold with balanced melt filling and cooling, and for which the mold cavity dimensions were engineered for an appropriate shrinkage.