Calibrator modelling in the simulation of extrusion process

Technical polymer profiles are often extruded while dragging them into a water bath. However, complex profiles may require additional forming tools. For example, geometrically complex profiles, such as PVC-window frames, require the use of a series of calibrators for satisfying severe geometric requirements. Calibrators are also required for rapid and homogeneous cooling as well, they must however be designed in such a way to minimize the temperature gradient along the profile thickness and hence to minimize the residual stresses of thermal origin. Within the context of numerical simulation of extrusion flows, a calibrator brings an additional downstream constraint to the kinematic equation which governs the extrudate surface shape. In the present paper, we propose a simple engineering approach for modelling calibrators used in profile extrusion, and we apply it to the non-isothermal simulation of the extrusion process for a 3D non-symmetric profile.