Computer Simulation of Plastics Sheet and Film to Help Slit Die Design

Abstract

This research objective is to study a coathanger die for plastics sheet and film manufacturing. Toextrude the molten plastics through the die, engineers need to control the constant outlet pressure across thedie width to maintain the uniform outlet velocity. The geometrical variations of the die such as the manifoldradius, slit height and width affect shear stresses and thus the flow fields in the slit die. In this study, a powerlaw fluid flow in the slit die is simulated by using Fluent, a commercial program. All parameters aredescribed through dimensionless groups, thus one creates dimensionless charts from the relations betweenthe dimensionless parameters helping extrusion die engineers to design a coathanger die for a specificplastics sheet and film.

Keywords : Coathanger Die / Plastic Sheet / Slit Die / Die Design