Three-Dimensional Simulation of the Non-Isothermal Cast Film Process of Polymer Melts

A modeling system is proposed to simulate the non-isothermal three-dimensional cast film process of viscous polymer melts. The finite element method (FEM) is used to solve the system and the numerical results are compared with the experimental measurements, including temperature, velocity fields, and final film shape. It is found from these results that the model is able to predict the film shape accurately under the steady-state processing conditions. The model considers the flow in the thickness direction, shear-thinning, non-isothermal effect, self-weight, and viscous dissipation, but it excludes die swell at the die exit, elasticity of materials, crystallization, and film sag. Using the model, the influence of temperature variation, draw ratio, and air gap length on the final film shape is also investigated.