Effect of raster orientation on the mechanical and surface properties of FDM-printed TPU

This study investigates the effect of raster orientation on the mechanical and surface properties of FDM-printed TPU 68D. Tensile, flexural, hardness, and surface roughness characterization were performed under standardized conditions using specimens printed with 0°, ± 45°, and 90° raster orientations. Tensile behavior showed clear anisotropy, with the 0° orientation achieving the highest strength (~ 24.5 MPa), modulus (~ 570 MPa), and elongation (~ 400%), while ± 45° and 90° samples exhibited reduced performance. This behavior is attributed to differences in filament alignment relative to the loading direction. In contrast, flexural response and hardness showed only limited variation between raster orientations, suggesting that these properties were less sensitive to internal raster alignment under the tested conditions. Surface roughness was also affected by raster orientation, with the ± 45° configuration producing the lowest roughness values. Overall, the study provides an integrated experimental comparison of tensile, flexural, hardness, and surface roughness responses in FDM-printed TPU, offering practical guidance for selecting raster orientation according to the dominant performance requirement.