Computer aided optimisation of profile extrusion dies - Definition and assessment of the objective function

An objective function is proposed for use in optimisation of profile die de sign, and defined in terms of mass flow rates to topological partitions of the profile cross section. In a series of uPVC extrusion trial sits depende nce on land channel height is investigated for two profiles to assess its s uitability for gradient based optimisation of flow distribution. Preliminar y finite element flow simulations are carried out and comparisons of comput ed and experimental objective function values show that the mathematical mo delling should be extended to include extensional effects and draw down at the die exit. Examination of the experimental profiles indicates the limita tions of die optimization in determining the detailed geometry of the finis hed profile cross sections.