Effects of fused filament fabrication (FFF) process parameters on tensile and flexural properties of ABS/PLA multi-material

Multi-material fused filament fabrication (FFF) is an effective tool for manufacturing specimens with different materials integrated. This research studies the effect of printing speed, infill density, and raster angle on tensile and flexural strength of multi-material samples of ABS/PLA manufactured by the FFF process. The response surface methodology is used to design the experiments and determine the effect of each variable. Infill densities of 50, 75, and 100%, printing speeds of 15, 25, and 35 mm/s, and raster angles of 0°, 45°, and 90° are considered for printing the samples. The results showed that the infill density significantly affects tensile and flexural strength compared to the other parameters. Among the three levels of the raster angle, the zero-degree raster angle had the most significant effect on the tensile and flexural strengths. Moreover, a multi-objective optimization approach is applied to enhance both tensile and flexural strengths, and the results are subsequently compared with the experimental data. The maximum tensile strength (37.71 MPa) and flexural strength (69.8 MPa) were achieved at 100% infill density and a raster angle of 0 degrees, respectively. However, at a density of 100%, it was observed that the samples showed more brittle behavior.