Nonisothermal film casting of a viscous polymer

A finite element model is presented for simulating two-dimensional, nonisothermal film casting of a viscous polymer. The model accommodates the effects of inertia and gravity, and allows the thickness to vary across the width of the film, but excludes sag and die swell. Based on simulations, three factors are shown to contribute to reducing neck-in and promoting a uniform thickness for the sheet: the self-weight of the material for low viscosity polymers; nonconstant thickness and/or velocity profiles at the die; and cooling of the film, especially when localized cooling jets are employed.