Surface quality and material removal in magnetic abrasive finishing of selective laser melted 316L stainless steel

As one of the most important additive manufacturing (AM) techniques, selective laser melting (SLM) shows great potential in directly producing functional tooling and complex structural parts through layer-by-layer fabrication. However, some critical issues such as poor surface finish, insufficient dimensional accuracy and inadequate fatigue life need to be addressed systematically before SLM could be widely applied in industries. Though the capabilities of some conventional finishing techniques such as machining, abrasive finishing and electrochemical polishing on surface finish of components generated by SLM have been explored by some researchers, there is still a great research gap on finishing AM-ed surfaces uniformly due to their high complexity. In this paper, the effect of slope angle on surface finish of the samples fabricated by SLM is characterized by scanning electron microscope and profilometer. Magnetic abrasive finishing (MAF), as a flexible polishing technique, has been developed to polish the samples generated by SLM with different slope angles. Surface roughness and material removal rate are recorded and evaluated during MAF process. To reveal the underlying mechanism, an analytical model of material removal rate is devised by correlating initial surface roughness of workpiece generated by SLM with abrasive indentation depth, which eventually determines the total material removal volume in MAF process.