Optimisation of grit protrusion in the electro-discharge dressing process of large grit size CBN grinding wheels

The technology of superabrasive grinding has been developed in order to achieve high-quality finish in extremely hard and brittle materials. New application fields have appeared, but new problems must also be faced. The truing/dressing process has a direct influence on the grinding performance of the wheel. Mechanical dressing exhibits clear limitations, and therefore much research work has been done dealing with non-conventional dressing techniques. The problem is specially important in the case of CBN wheels, which require large space between grits in order to efficiently accommodate the swarf produced in the grinding of more ductile materials. Important limitations also appear in the case of large grit size wheels. In this paper, the electro-discharge dressing (EDD) process of 126# grit size CBN metallic bonded wheels has been analysed. The performance of the method is evaluated by measuring grit protrusion and relating this parameter to grinding forces.