To design an optimal coathanger die with a uniform flow rate distribution and low pressure drop, it is significant to understand the flow conditions in the die. This is important because the quality of the product is influenced by the flow velocity and the flow rate distribution. In extrusion dies occurs next to the main flow also cross flows, which flow perpendicular to the main flow. This results in pressure gradients in extrusion direction, influence of flow distribution and pressure drop in the die. In recent decades quantitative representation and analysis of physical flow processes have made considerable progress in predicition of the weather, the development of drive technologies or design of aircraft using simulation methods and lab trails. Using the pathline method, the flow is be analyzed in flat film extrusion dies with a rectangular cross-section, in particular cross flows. The simplest method to visualize the flow is based on measurement of obstacle orientation in the flow field by addition of individual particles. A near-surface flow fields can be visualized by using wool or textile yarns. By sticking thin, frayed at the ends of strands of wool surface that is to be examined, near-wall profiles of the flow and vortex and separation regions can be visualized. A further possibility is the addition of glass fibers and analization of fibre orientation by microscopy and x-ray analysis. In this paper the influence of process parameter (p.e. melt temperatures and through put) on cross flow and fiber orientation are presented. Keywords: flat die, extrusion, cross flow, orientation *Corresponding Author: Bianka Henke, Bianka.Henke@ktp.upb.de