Surface Topography Improvement of Micro-Milled Inconel 718 Slots Through Abrasive Deburring: Comparison Between Polishing and Sanding

Burr formation remains a major challenge in micro milling due to reduced tool dimensions and size-effect phenomena, particularly when machining difficult-to-cut materials such as Inconel 718. This study compares the effectiveness of two abrasive deburring processes, polishing and sanding, applied to micro-milled slots, focusing on burr removal and surface topography modification. Twelve 15 mm long slots were machined using a 400 µm diameter TiAlN-coated micro end mill under constant cutting conditions. Deburring was performed for 1, 2, and 4 min for polishing and for 30 s for sanding. Surface topography and burr height were evaluated before and after each process. The results revealed significant burr formation, with burr heights reaching the same order of magnitude as the axial depth of cut and higher values on the down-milling side. Polishing showed limited deburring capability, primarily promoting burr deformation while reducing surface roughness by up to 21%. In contrast, sanding reduced total height of the burrs by up to 99% and generated flatter edge morphologies, although surface roughness increased by up to 19%. These findings highlight the trade-off between burr control and surface quality in the abrasive post-processing of micro-milled Inconel 718 features.