Structural deformation/instability of the co-extrudate rubber profiles due to die swell: Experimental and CFD studies with 3D models

Abstract

Co-extrusion is one of the most effective processes for manufacturing long polymeric profiles with two textures with different constituent rubber compound’s inherent properties. Typically, two rubber compounds are amalgamated with each other to construct hard and soft surfaces. This study investigates the die swell characteristics while extruding the two rubber components using the proper material properties. Herein, the EPDM rubber-based compound’s thermal and rheological parameters have been identified to predict the extrudate’s overall deformation profiles during the extrusion molding process. Carreau-Yasuda and Arrhenius approximate law exhibited an excellent fit for a wide range of shear rates with the experimental data. Finally, the extrudate’s overall deformation has been simulated using finite element software (ANSYS Polyflow®) at real processing conditions along with the boundary conditions (inlet, die wall, Interfaces, extrudate free surface, profile cross-section). Furthermore, numerical results generated from the simulation have been cross-verified with the experimental results for a complex-shaped rubber profile, and a good agreement with an efficiency of > 98.5% was obtained.