Evaluation of the Effect of Raster Angle on the Fracture Properties of 3D Printed Polycarbonate Using the Essential Work of Fracture Method

Abstract In this study, the effects of different raster angles (0°, 45°, 90°, and 0/90/0°) on the mechanical, fracture, and tribological performances of polycarbonate (PC) samples fabricated using fused-filament fabrication were experimentally investigated. The fracture behavior was evaluated using the essential work of fracture (EWF) method, and the results were interpreted along with tensile, dynamic mechanical (DMA), and tribological analyses to provide a comprehensive assessment. The 90° orientation exhibited brittle fracture behavior with a negatively sloped regression line, indicating the limited applicability of the EWF approach under this condition, whereas the 0/90/0° configuration exhibited the highest fracture toughness. Tensile tests revealed that the 0/90/0° specimen had the highest tensile strength, whereas the lowest value was recorded for the 90° orientation. These results highlight the strong influence of filament orientation on the load transfer behavior. The DMA results showed that the storage modulus of the 0/90/0° sample remained more stable across a range of temperatures, indicating improved thermomechanical stability compared to other configurations. In the adhesive wear test, the 0/90/0° orientation exhibited the lowest coefficient of friction (COF) and minimum surface deformation, whereas the 90° orientation exhibited the highest COF and weakest wear resistance with irregular wear patterns. Overall, the findings demonstrate that multidirectional raster configurations, particularly 0/90/0°, provide a more balanced performance across the mechanical, fracture, and tribological properties. Consequently, filament orientation is a critical factor in the performance of PC-based 3D-printed parts and can be considered as a design parameter for optimizing functional performance in engineering applications. Graphic abstract