Comparative Analysis of Micro-Machining of 316L Stainless Steel Fabricated by Laser Powder Bed Fusion, Laser-Wire Directed Energy Deposition and Conventional Methods

The demand for miniature 316L stainless steel components in critical sectors is increasingly met by additive manufacturing (AM); however, due to the increasing applications of 316L in advanced manufacturing industries, there is a need to identify the machinability performance for 316L based on the fabrication techniques for addressing challenges. This study investigates the micro-machining performance of 316L material fabricated via Laser Powder Bed Fusion (LPBF), Laser-Wire Directed Energy Deposition (LW-DED), and conventional (wrought) methods. Results reveal wrought 316L exhibits superior machinability, yielding the lowest cutting forces, surface roughness, burr heights, and tool wear. Compared to the wrought baseline, average cutting forces increased by 10.5% for LPBF and 41.4% for LW-DED. Areal surface roughness deteriorated by 12.3% for LPBF and 52.1% for LW-DED. Average maximum down-milling burr heights were 35.6% and 48.8% higher for LPBF-316L and LW-DED-316L, respectively, than for wrought 316L. The observed ranking of machining responses was associated with the specific material conditions investigated. SEM observations and microhardness measurements indicate morphological and hardness differences among the specimens, which may have contributed to the measured differences in cutting force, surface roughness, burr formation, and qualitative tool-condition observations. As a result, process-induced specimen variations fundamentally govern the micro-machinability of AM 316L, offering critical insights for optimizing post-processing operations.