Vibratory Finishing of Laser Powder Bed Fused Stainless Steel 316 Internal Cooling Channels

Abstract

The Laser-powder bed fusion process (L-PBF) offers the advantage to manufacture tools and dies with cooling channels precisely following the component contour. The L-PBF manufactured cooling channels have poor surface finish quality. We enhance the internal surface quality of cooling channels—to reduce the risk of ineffective cooling—through the vibratory finishing process. Surface finishing reduces the cooling time drastically to increase production efficiency. We improved the surface finish quality of linear and non-linear L-PBF stainless steel 316 cooling channels. To improve the media flow inside the cooling channels during the vibratory finishing process, we used 98.4% mass concentration of satellite media, 0.738% mass concentration of water, and a 0.837% mass concentration of 10 µm sized SiC abrasives. We polished the channels for 5 h. Additionally, we conducted a discrete element method (DEM) simulation to understand media flow in the differently shaped channels when subjected to vibratory finishing. Lastly, we discussed the changes in channel surface characteristics and suggested methods to surface finishing the more complex internal channels through vibratory finishing.