And the first normal stress difference near the exit of die increases with relaxation time increasing which result in the extrusion die swell and the warpage of side walls increasing.

• 此外，随着松弛时间的增大，口模出口附近气辅段的第一法向应力差增加，从而导致离模膨胀和两侧壁向内的翘曲变形均增大。