Post-processing of powder bed fused stainless steel: micro-machining and micro-electrical discharge machining

Surface quality is often a specific requirement when dealing with Additive Manufacturing and dimensional accuracy, especially during 3D printing of metals. Therefore, it is crucial to evaluate the material removal behavior of Powder Bed Fusion specimens during Micro-Mechanical Machining and Micro-Electrical Discharge Machining procedures to detect their machinability responses. In this paper, micro-machining of 17-4PH stainless steel samples produced by Laser Powder Bed Fusion is reported. Specifically, we performed Micro-Mechanical Machining and Micro-Electrical Discharge Machining operations, analysed the process performances, and compared the machining conditions. Additionally, we investigated the surface roughness and burrs extension as a function of geometrical configuration and process parameters. The outcomes of this work regard the processing conditions and parameters to optimize the machining operations on 3D-printed metal samples. This work allows the identification of specific features resulting from each process in relation to the material removal rate, giving the possibility to compare and evaluate the machining conditions for 3D parts post-processing.