砥粒切れ刃の摩耗は，砥石作用面上の切れ刃分布や切れ刃形状を変化させて砥石寿命並びにそれに至るまでの研削特性を支配する主要因となるため，従来からその挙動に関する多くの研究が行われてきた．しかし，切れ刃形状の複雑さやその分布の不規則性などから摩耗挙動を定量的に把握することはいまなお困難である．%This paper deals with a three-dimensional (3D) fractal analysis of wear process of cutting edges in cBN grinding. Wear behavior of grain cutting edges in the grinding process with vitrified cBN wheels has been observed using 3D-scanning electron microscope with four electron probes and the 3D surface profile of cutting edge has been evaluated by means of the fractal analysis. Wear mode of cBN grain cutting edges can be characterized by the fractal dimension. The fractal dimension for the surface profile of cutting edge formed by brittle attritious wear is higher than that of cutting edge formed by ductile attritious wear or fracture wear. Therefore, an increase in ductile attritious wear flat on the grain cutting edge results in a decrease of the fractal dimension. In addition, the complicated changes in shape of cutting edge due to self-sharpening can be evaluated quantitatively by the fractal dimension.
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