Effect of raster angle on the tensile and flexural strength of 3D printed PLA+ parts

In fused deposition modeling (FDM) 3D printing, the properties and performance of the fabricated components are profoundly affected by the selected process parameters. Therefore, it is crucial to choose and optimize these parameters to improve the quality and mechanical characteristics of the final product. Given this, the present study explored the mechanical properties of 3D-printed components fabricated from polylactic acid (PLA)+ filament, specifically examining how different raster angles influence their flexural and tensile performance. Three raster angle conditions were investigated: parallel (0°/0°), grid (0°/90°), and crisscross (45°/−45°). The results demonstrate that the raster angle has a significant effect on the flexural and tensile strength of the printed specimens. The parallel raster (0°/0°) produced the highest flexural strength, attributed to the alignment of the fibers perpendicular to the applied load, which enhances the load capacity. Conversely, the crisscross (45°/−45°) orientation resulted in the lowest flexural strength but exhibited greater ductility, as evidenced by extensive plastic deformation. This increased ductility is attributed to the material's ability to absorb more energy before failure, resulting from favorable shear deformation dynamics. In tensile testing, the parallel raster (0°/0°) showed superior strength, while the grid and crisscross orientations followed with progressively lower values. The fracture behavior revealed that samples 3D printed with a 45°/−45° raster angle tend to fail along the raster orientation, primarily due to the development of shear stresses.