The plasticizing unit and its barrel/screw configuration is a major functional component of an injection molding machine. Striving for cycle time minimization, higher output rates and improved melt quality is inevitable to keep up with market requirements. For this reason, the development moves towards high-performance single screws. As described in previous papers [1] [2], a new simulation software has been developed to predict the optimum screw geometries and process parameters for the respective application. This work focuses on grid generation, geometry represetation and process simulation using barrier screws. Our development of a novel method for grid generation and grid visualization enables to generate a 3D model of the unwound channel of a barrier screw. Basis is a two-dimensional CAD drawing containing all relevant parameters, which are necessary to describe the solid and melt channel. This transformation does not require a cylindric coordinate system, but instead uses cartesian coordinates. The simplicity of this coordinate system, respectively the 2.5-dimensional grid used in simulation, significantly reduces computational costs and simulation time compared to conventional CFD programs. In combination with improved user-friendliness and the possibility of a 3D representation of the complex channel geometry, this method is a crucial development in modern process simulation.