Effect of raster angle on mechanical properties of 3D printed short carbon fiber reinforced acrylonitrile butadiene styrene

The most common additive manufacturing technique fused filament fabrication (FFF) suffers from inter-bead porosity that reduces mechanical properties. Inter-bead pores follow the raster angle, which causes anisotropic mechanical properties. Yet, the effects of raster angle on the mechanical behavior of short-carbon-fiberreinforced (SCFR) thermoplastics are unclear. In this study, we performed tensile, flexural, and fracture toughness tests on SCFR acrylonitrile butadiene styrene (ABS). Raster angles of 0 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, and 90 degrees were investigated. Tensile strength and elastic modulus decreased by 22-35% for a change from 0 degrees to 15 degrees. Flexural strength and modulus were less sensitive to raster angle. Flexural strengths were at least 50% more than tensile strength for the same raster angle. Whereas flexural modulus is at least 15% less than elastic modulus. Fracture toughness showed a non-linear relationship with the raster angle. Maximum fracture toughness was observed at 0 degrees and 60 degrees rasters. Crack deflection was observed as the toughening mechanism.