This work was realized in collaboration with the Continental Group with the aim to study the fluid dynamic behaviour of a Single Screw Extruder (SSE) used in their R&D laboratories. The work was carried out using a computational fluid dynamics (CFD) code named ANSYS Polyflow which adopts the Finite Element Method (FEM) for discretising the transport equations. Two kind of geometries were realized: the one of interest to the Continental Group, referred to as the Nominal Geometry and characterized by empty spaces interrupting the thread of the screw, and the Full Screw Geometry, similar to the previous one but with a continuous thread.