3310 Permeability of Sintered Porous Metal in Finishing Process with Grinding and Electrical Discharge Surface Modification

This paper concerns the machining process of the porous metal bushing for aerostatic bearings. The change in air permeability of the bushing is investigated during the grinding process which is employed to improve the form accuracy, and it is found that the permeability has decreased with the significant fluctuation as the removal volume increases. Then, the electrical discharge surface modification is proposed as a flexible post process to re-increase the permeability. After the process with a small scanning electrode, re-solidified layer has been generated on the surface of bushing and the increase in permeability has been confirmed.