Enhanced drilling process to improve hole quality of additively manufactured Inconel 718 Alloy

Post-processing plays a critical role considering the product fabricated by additive manufacturing process. The hole produced in the additively manufactured products requires additional attention in terms of surface and subsurface quality. In this study, drilling was applied to improve the hole quality of Inconel 718 alloy manufactured by powder bed fusion-laser beam (PBF-LB) method. Inconel 718 alloy manufactured under different PBF-LB process parameters was drilled with sharp corner, radius corner, and chamfer corner drill bits. The measured outputs were the surface quality of drilled hole, surface topography, surface and subsurface microhardness. This study showed that drilling process helps to improve the surface quality of additively manufactured Inconel 718 by reducing the surface roughness. Depending on the geometry of cutting edge of drill bit used in drilling operation, it is possible to improve surface quality by 90% comparing to the as built quality.