The cast-film process is widely used to produce synthetic (polymer) film for a large range of applications. Two geometrical defects contribute to decrease efficiency of this process: the width reduction (necking defect) and the inhomogeneous decrease of the thickness distribution (edge bead defect). In this paper, a numerical simulation of the process is performed to predict these defects. A membrane approximation is used to reduce the equations to a 2D model. The polymer flow is non-isothermal (heat transfer coefficient is discussed) and a viscoelastic constitutive equation is accounted for. (c) 2006 Elsevier B.V. All rights reserved.