Effect of AC Electric Field Polishing with Abrasives on cBN and Cermet Cutting Tool Wear

Abstract

This paper describes the effect of AC electric field polishing (EFP) on the cutting tool wear. The authors have been studying the novel polishing method for wear reduction of the tool edge. The polishing apparatus with the free-abrasives control technology with AC electric field was developed. It is found that the increase of the flank wear using an AC electric field was suppressed. In this work for a detail investigation of the EFP mechanism, we investigated the effect of AC electric field on the cBN or Cermet tool edge surface after EFP. Then, the motion of abrasives around a tool edge in AC electric field was confirmed. In order to clarify the effect of AC electric field, we measured the surface roughness of the edge and the radius of curvature of the cBN and Cermet tool after polishing with and without AC electric field. The surface roughness with AC electric field was smaller than that without AC electric field, and the amount of the increase was the almost the same on the condition of both with AC electric field and without it. In addition, the motion of abrasives around a tool edge in AC electric field was evaluated. Results showed that diamond abrasives gathered around the tip of the cutting tool edge even when a tool edge and a polishing pad were away from each other in AC electric field. Finally, hypothesis of the effect of EFP on the edge surface was showed. It was that abrasives gathered by AC electric field at the portion of the tool edge not plunged in the polishing pad is able to remove the weak portion of the surface of the sintered body and only the strong bonded portion is likely to remain during polishing.