This paper presents the results of a study of the implementation of CAD/CAE methods in the design of polymer processing machines. As is well known, polymer plastic components are a large percentage of automotive vehicle construction. Plastics are used to manufacture vehicle interior, body, drivetrain, electronic components and chassis components. These components are produced using injection moulding and extrusion technologies. This paper focuses on extrusion technology and the object of study was the extruder head. The benefits obtained from the application of the methods were indicated, as well as the aspects to which special attention was paid during the implementation of these methods. Simulations of the injection point's contribution to filling were obtained for plastic flow in the extruder head workspace. The results of these simulations form the basis for modifying selected geometrical features of the head, mainly the shape and depth of the notches on the outer surface of the head. In addition, the pressure range in the working space between the outer surface of the head and the inner surface of the entire head housing was indicated.