Design and optimization methodology for different 3D processed materials (PLA, ABS and carbon fiber reinforced nylon...

This research presents a methodology for the design and optimization of 3D printed parts with material extrusion (MEX) technology with three different commercial materials: PLA, ABS and N + CF (PA12) subjected to tensile and fatigue stresses, which included three stages: pretreatment, design of experiments and sequential optimization by statistical modeling. In the pretreatment stage, mainly the printing control factors (inner layer and contour height, printing speed, extrusion temperature, nozzle, infill arrangement and printing orientation) were determined; then, factors to optimize tensile strength as a function of printing pattern (linear, 3D, hexagonal), infill percentage (33%, 66%, 100°) and printing orientation (+45°/-45°, 0°/90°) were evaluated. Fatigue analysis was performed as a function of impression orientation using 100% infill, linear impression pattern, 5 Hz and a load range between 90 and 50% UTS. Optimization of tensile strength resulted in parts that exceeded the UTS of their corresponding filament, leading to infinite life relative to fatigue tests. Results were presented for fatigue life prediction based on Weibull analysis, Basquińs model and a multivariate response surface correlation analysis. The best fatigue behavior was related to the optimized tensile strength, the infill pattern applied to the printing orientation and the intrinsic properties of ABS (1 × 10⁷cycles, stress up to 20 MPa). With respect to the other materials, a good fatigue behavior was highlighted at the number of cycles achieved 1 × 10⁶ (stress up to 18 MPa) and 1 × 10⁵ (stress up to 24 MPa) for N + CF and PLA, respectively. This study contributes to a better understanding of how printing parameters correlate with tensile and fatigue properties.