Flow restrictor design for extrusion slit dies for a range of materials: Simulation and comparison of optimization techniques

Based on a finite element simulation of slit die performance that takes into account the coupling of melt flow and die body deflection due to melt pressure, a genetic algorithm, a multipoint approximation optimization technique, and a gradient-based optimization technique are applied to determine choker bar profiles to give optimum melt flow distribution. The performances of the optimization methods are compared with respect to efficiency and ability to obtain a global optimum. This work involves three materials of varying degrees of shear thinning, each at a high and a low flow rate. The developed software makes it possible to predict whether restrictor adjustment can produce acceptably uniform flow distribution in a given application, using a given die, and shows what restrictor profile should be set up, thereby eliminating or reducing the need for on-line trial and adjustment, and establishing if the same die can be used for a range of materials to reduce costs.

[1]  Chester Miller,et al.  Predicting Non-Newtonian Flow Behavior in Ducts of Unusual Cross Section , 1972 .

[2]  J.F.T. Pittman,et al.  Thermal Effects in Extrusion: Slit Dies , 1994 .

[3]  Daniel A. Tortorelli,et al.  Optimal design for polymer extrusion. Part I : Sensitivity analysis for nonlinear steady-state systems , 1998 .

[4]  V. Markine,et al.  Refinements in the multi-point approximation method to reduce the effects of noisy structural responses , 1996 .

[5]  D. Owen,et al.  Finite element software for plates and shells , 1984 .

[6]  Mustafa Özakça,et al.  Analysis and optimization of prismatic and axisymmetric shell structures : theory, practice and software , 2004 .

[7]  H. Henning Winter,et al.  Design of dies for the extrusion of sheets and annular parisons: The distribution problem , 1986 .

[8]  J. Pittman,et al.  Simulation of slit dies in operation including the interaction between melt pressure and die deflection , 1996 .

[9]  Vassili Toropov,et al.  NEW DEVELOPMENTS IN STRUCTURAL OPTIMIZATION USING ADAPTIVE MESH REFINEMENT AND MULTIPOINT APPROXIMATIONS , 1997 .

[10]  Tai-Yong Lee,et al.  Shape optimization of polymer extrusion die by three-dimensional flow simulation , 1997, Proceedings High Performance Computing on the Information Superhighway. HPC Asia '97.

[11]  Daniel A. Tortorelli,et al.  Optimal design for polymer extrusion. Part II: Sensitivity analysis for weakly-coupled nonlinear steady-state systems , 1998 .

[12]  John H. Holland,et al.  Adaptation in Natural and Artificial Systems: An Introductory Analysis with Applications to Biology, Control, and Artificial Intelligence , 1992 .

[13]  Johann Sienz,et al.  Enhancing slit die performance by optimization of restrictor profiles , 2003 .

[14]  W. Stannek,et al.  Mechanical Effects in Extrusion: Slit Dies , 1995 .

[15]  David E. Goldberg,et al.  Genetic Algorithms in Search Optimization and Machine Learning , 1988 .

[16]  Xueyu Ruan,et al.  Computer-aided design of extrusion dies , 1988, Comput. Graph..

[17]  van der Erik Giessen,et al.  SIMULATION OF MATERIALS PROCESSING: THEORY, METHODS AND APPLICATIONS , 1998 .

[18]  C. Lawson.  Software for C1 interpolation , 1977 .

[19]  Vassili Toropov,et al.  Simulation approach to structural optimization , 1989 .

[20]  Valeri Markine.  Optimization of the Dynamic Behaviour of Mechanical Systems , 1999 .

[21]  Vassili Toropov,et al.  Multiparameter structural optimization using FEM and multipoint explicit approximations , 1993 .