Locational Dependency of Additively Manufactured Parts: Effects of Surface Roughness on Fatigue Behavior

Surface roughness (SR) can vary significantly among parts manufactured at different locations on the same build platform because of the gas flow and powder recoating process in current laser beam powder bed fusion (LB-PBF) technique. In this study, intra-build SR variation across locations was investigated for LB-PBF 316L stainless steel. The build platform was divided into 4 quadrants to assess the location-dependent variation of SR. Uniaxial stress-controlled fatigue tests were conducted using a servo-hydraulic system. The SR from the four quadrants was analyzed using the one-way Analysis of Variance (ANOVA) method and further verified SR's location dependency. Kruskal-Wallis test was also employed since Box-Cox transformed data failed to meet the requirements of the ANOVA test. Kruskal-Wallis test revealed that there are statistically significant differences in SR values across different locations. The results were validated using fatigue test results and gas flow simulation results reported in literature.