FINITE-ELEMENT ANALYSIS OF POLYMER MELT FLOW IN PROFILE EXTRUSION COATING DIE

Automotive side protection moldings, which consist of polymer and an inserted metal core, are produced by profile extrusion coating. The molding process is similar to wire coating process except using a cross-head profile die because the cross-sectional shape of the side protection molding is complex. The polymer is extruded from the profile die covering the metal core, which is fed to the die simultaneously. Then, there are two flow regions within the profile die. One is pressure flow region where the polymer is flowed by pressure gradient. Another is drag flow region including pressure flow. The drag flow appears in the area where the polymer contacts the moving metal core in the die. Finite element analysis was developed for simulating the combined pressure and drag flow in a complex profile die. The flow is assumed to be isothermal planner flow for a non-Newtonian fluid. Power law model is used to represent viscosity of the polymer. Distributions of pressure and velocity are simulated by the analysis. Polymer melt flow through a flow channel of a die for producing the side protection molding was analyzed to achieve uniform velocity at the outlet of the die. A suitable shape of the flow channel was designed by several iterative simulations.