Comparison of Polishing Methods: The Effect on The Surface Roughness and Fatigue Performance of PBF-LB manufactured 316L Stainless Steel

Stainless steel 316L is currently one of the most prominent materials on the AM industry including the laser powder bed fusion (PBF-LB) manufacturing. The surface roughness of the PBF-LB manufactured material is typically over 10 μm in terms of Ra and this can have a detrimental role in the fatigue resistance of the parts. However, several techniques and machines are now available to reduce the surface roughness, but no comprehensive data is available on the limits or the effectiveness of those. In this paper, the performance of four commonly available techniques is analyzed utilizing equal PBF-LB manufactured 316L samples. The results show the effect on the surface roughness and also the surface profiles and topographies are analyzed. Up to 80% reduction in the surface roughness R
a
could be reached. Moreover, the effect of each polishing method on the fatigue performance in bending fatigue testing was analyzed. The results showed that the fatigue limit of the 316L can be tripled even when mirror finish is not reached.