Flow Balancing in Extrusion Dies for Thermoplastic Profiles

To achieve a specified geometry for an extruded profile, to-gether with a minimal degree of internal stresses, flow balan-cing of the die is required. To attain this objective, the flow along a profile die channel must be accurately described, and this demands a computational code able to predict complex 3D non-isothermal flow patterns. In this work new methodolo-gies for flow balancing are implemented and illustrated. The design code developed to carry out the automatic search of a fi-nal geometry consists of an optimisation routine coupled with geometry and mesh generators and a 3D computational code based on the finite volume method. The issues discussed and described here encompass recent developments, namely the im-plementation of two alternative optimisation algorithms for the automatic search of a final solution, the enhancement of the strategies previously developed to balance the flow, some im-provements in the routine used to generate the mesh and the adoption of a progressive mesh refinement technique. The ex-amples show that the proposed methodology performs well and the solution is attained in just a few minutes of calculation without any user intervention during the calculation process.