Introduction Melt filtration plays an important role in improving material quality, particularly in relation to polymer recycling, as it ensures that the melt stream is suitably clean and free of contaminants such as paper, metals, wood, foreign plastics, glass, dust particles, unmelted or degraded polymer formations. Optimization and Modeling The performance of a double-cavity piston screen changer was improved by rheological optimization of the flow geometry based on analytical calculations and numerical CFD simulations. We optimized the geometry of flow channels and breaker plate in order to increase their self-cleaning capacity, decrease residence time of the melt in the filter and reduce pressure drops, thus enabling gentle processing of various thermoplastic polymers. For the layout of a filtration process, the initial pressure drop of the polymer melt and the separation performance of the filter must be determined. An improved model allows the calculation of the pressure drop in a polymer melt flowing through woven screens as a function of mass throughput and polymer properties. Results Designing a melt filter with optimized flow geometry means balancing conflicting requirements. While achieving small pressure drops calls for increased diameters of the flow channels, short residence times and high wall-shear speeds for efficient self-cleaning require diameters to be reduced. The performed numerical und analytical calculations yielded an optimal design that takes into account all parameters. As a result, for a given pressure drop, the average residence time could be reduced by 13% and the wall-shear speed increased by 15%. In addition to the optimized flow geometry, we present a novel mathematical model for calculating the pressure drop based on heuristic algorithms. The model can be applied for polymers flowing through square-woven and twilled-dutch screens, and was validated using a variety of in-house recycling materials, throughputs and filtration fines.