Abstract

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 Direct 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. Maximum side burr heights increased up to 35.6% and 48.8% for LPBF and LW-DED, respectively. Wrought-316L's optimal performance is driven by its homogeneous, equiaxed microstructure, facilitating stable shearing. Conversely, LW-DED's coarser grains and ductility promote severe plastic side flow and catastrophic adhesive tool wear. LPBF showed intermediate machinability; its elevated yield strength restricted thermal smearing, but reduced ductility and inherent micro-defects induced micro-tearing and accelerated tool wear via coating delamination. Ultimately, process-induced microstructural variations fundamentally govern the micro-machinability of AM 316L, offering critical insights for optimizing post-processing operations.