Optimizing 3D Printing Parameters of Thermoplastic Elastomer Granules for Application in Topology-Optimized Designs

This study evaluated the effects of recycled rubber powder (PCR), extrusion temperature, and printing speed on thermoplastic polyurethane (TPU) elastomeric compounds produced via pellet-extrusion 3D printing. A factorial design was employed to analyze specimens with varying PCR contents. Increasing PCR content decreased tensile strength and impact toughness, while slightly increasing Shore~A hardness. Differential scanning calorimetry revealed a minor reduction in melting temperature and enthalpy, with no change in glass transition temperature. Optimal conditions were identified as 220 °C, 30~mm/s, and 10% PCR. A topology-optimized shoe sole fabricated under these conditions exhibited high dimensional accuracy, confirming the feasibility of the process and its potential for sustainable applications in footwear and impact-absorbing devices.