Novel Polishing Method of Cutting Edge Using AС Electric Field for Controlling Flank Wear

Abstract

Polycrystalline cubic boron nitride (cBN), a super-hard material used for hard turning, has good compatibility with steel. However, because chipping occurs from already existing defects and worn out cutting edges, a cBN insert must be exchanged within a short cycle time. By reducing chipping and flank wear, one can reduce the tool costs related to cutting processes and reduce the number of times the insert has to be exchanged, leading to improved productivity. In this study, the authors hypothesize that chipping and flank wear during cutting reduced by polishing a tool edge finely, uniformly, and smoothly before cutting. An apparatus capable of polishing and smoothing a cutting tool edge uniformly is developed. In the free-abrasive control method, application of an AC electric field during polishing is applied to suppress the scattering of abrasives from the tool cutting edge. Results show that scratches created by grinding are nonexistent. Moreover, a smooth cutting edge is obtained after polishing treatment. The wear width of the polished cBN tool under a cutting speed of 50 m/min is half of that of the non-polished treatment tool. Furthermore, no chipping occurs with the polished cBN tool under any conditions. Additionally, results show that the same effect is obtained even when Silicon carbide (SiC) abrasives are used. The n value calculated using the Taylor tool life equation is almost identical in cases of both diamond and SiC abrasives.