Processing of rigid PVC is still a challenging job. Within standard plate extrusion, people design a coathanger extrusion die with rather universal die dimensions allowing to process a wide range of materials in a wide range of temperatures. For most of the thermoplastic polymers, one does not have to take into account slip at wall behaviour. In extrusion for rigid PVC, it is well known that the slip at wall behavior has to be taken into account. Especially, if one concentrates on processing of recycled PVC materials, accurate material characterization should be done to end up with a good material behaviour prediction for rheological parameters. For materials sticking at the wall, theoretical formulas exists to define the changing radius along the width of the coathanger die. Within this prediction, one assumes isothermal processing (the effect of shear heating is neglected). In case of materials which are sensitive for slip at wall, no theoretical formulas are present. To avoid too demanding 3D numerical simulation models to come up with a good design for equal material distribution along the width, a 1D nodal approach has been developed to take into account the slip at wall behaviour combined with the shear heating for this high viscous materials. With this 1D tool, the influence of changing slip at wall parameters can be clearly indicated without too much computational efforts. It allows to come up with a robust die design that is validated with a full 3D finite element simulation.