Fractal Analysis of Wear Behavior of Grain Cutting Edges in cBN Grinding

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.