Knowledge of residual stress in machined and molded polymer parts is important in terms of understanding both dimensional stability and susceptibility to chemically assisted cracking. Residual stresses can be present in extruded stock shapes, molded parts, and thermoformed products. These stresses may be a normal part of the manufacturing process due to thickness changes or uneven cooling Residual stresses can also be present due to non-uniform flow rates or inclusions. Machi