Experimental and numerical investigation of rotating bending fatigue of polylactic acid 3D printed parts by an extrusion-based additive manufacturing method

This study investigates the impact of four parameters, namely layer height, nozzle temperature, infill percentage, and bed temperature, on the fatigue life of polylactic acid (PLA) printed parts using the extrusion-based additive manufacturing (AM) process. The experiments were designed using the Taguchi method, considering three levels for each parameter. The extent of the impact and the optimal values of the process variables were determined by using analysis of variance (ANOVA) and signal-to-noise ratio. To predict the fatigue behavior, an empirical model was presented, which was fitted to the fatigue results of the samples made with the optimal process variable values using the least squares method. Additionally, finite element simulations were conducted, and the results were compared with the experimental study findings. The results indicated that the optimal process variable values for maximum fatigue strength are a layer height of 0.3 mm, a nozzle temperature of 220 $℃$, a 100 % infill and a bed temperature of 60 $℃$. The ANOVA results revealed that the infill percentage, nozzle temperature, and layer height have the greatest influence on fatigue life, with respective contributions of 60.5 %, 28.1 %, and 7.7 %. The experimental modeling and finite element simulation results indicate that the proposed models predict fatigue behavior with regression coefficients of 96.3 % and 98.7 %, respectively.