Numerical investigation of weather strip extrusion forming process by thermal flow analysis

Abstract

The weather strip used to protect the interiors of vehicles from rainwater, dust, and noise is manufactured through the special extrusion forming process in which the solid-state rubber material is forced to be compressed, melted, and extruded out through the forming die. The extrusion forming process is characterized by the thermal flow of melted rubber material, which is in turn influenced by the slip condition at the inner wall of the head and the shear viscosity as well as the flow vorticity. The die design, which substantially affects the extrusion forming quality, is made based on the thermal flow characteristics, particularly in the head region. In this context, this paper is concerned with the numerical investigation of thermal flow characteristics in the head region by the finite element analysis. The flow profile, streamlines, and the temperature distribution are investigated with respect to the breaker plate, wall slip condition, and the shear viscosity model. The extrusion forming using twin dies is investigated as well with respect to the imbalance of the wall temperature and inlet flow velocity.