Effects of raster angle and composition of layers on tensile and flexural properties of PLA-PLA/Al multimaterial manufactured by fused deposition modeling

This paper fabricated two-material parts of neat PLA and PLA/40% Al composite by fused deposition modeling (FDM). The mechanical properties of this multi-material depend on the correct choice of 3D printing parameters. Thus, the effect of raster angle and composition of layers (both position and number of layers) on standard samples' tensile and flexural properties were investigated. The 3D printed samples consisted of ten layers, each with a thickness of 0.3 mm. The full-factorial method is used for designing the experiments. In this design, the raster angle, number of composite layers, and position of the composite layers were set to (+/- 45 degrees, 0 degrees/90 degrees), (2, 4, and 6), and (top and mid), respectively. The results showed that the tensile strength decreases with the number of composite layers. Furthermore, it was found that the raster angle of 0 degrees/90 degrees, using just two composite layers and placing the composite layers in the top layers of the samples, provides the best tensile and flexural properties. Additionally, a scanning electron microscopy (SEM) investigation of the samples' fractured sections revealed that the composite material exhibits ductile behavior when reinforced with Al particles. On the other hand, the presence of the particles aided in the formation and proliferation of cavities, eventually leading to the premature sample's failure.