Abrasive Flow Polishing of Micro Bores

This report shares the feasibility study results of abrasive flow polishing of microbores of size φ500 μm or smaller and 25∼50 in aspect ratio for both metal and ceramic materials. A polishing device was designed and built up so as to create enough turbulence for facilitating the polishing at the inner walls of the micro-bore. Polishing of micro-bores on 3 materials: S45C, SS304 and Zr2O3 of length 13.6 mm, were conducted. Surface roughness and topography of the polished inner walls were studied using profilometry and optical interferometry form the three dimensional point of view. Significant progress in surface roughness in all inner walls has been made in the polishing process. The results indicate that it is feasible to apply abrasive flow polishing for metal and ceramic micro-bores of diameters smaller than 500 μm. It is also found that the surface roughness of the inner wall decreases with the increasing number of slurry flow pass at a relatively constant applied pressure. However there exists a critical number of flow passes beyond which the improvement in surface quality is marginal.