Abstract: Extrusion swell of L-shaped profiles during coating co-extrusion was analyzed by the Phan-Thien-Tanner (PTT) constitutive equations and finite element. It was found that the overall extrusion swell ratio kept constant when the thickness of core layer changed, but the swell rate in shell, core layer and along the X, Y direction of the concave right angle in L-shaped die were all changed dramatically. When the overall size of the die kept constant, the maximum shear rate at the die exit kept constant.

Key words: extrusion, profile, coat, die swell, numerical simulation