15 - Real Contact in Grinding

Abstract

To understand grinding behaviour, it is essential to draw a distinction between real contact and apparent contact in grinding. Both real and apparent areas of contact increase with grinding depth of cut, wear of the abrasive grains and elasticity of the wheel bond. Real contact area and apparent contact area are both essential to understand how grinding forces and grinding temperatures change during a grinding process. Conformity and real contact area also affect how an abrasive wheel wears in a grinding process. An elastic wheel spreads the grinding force over a larger area and reduces temperature peaks. However, an increase in real area of contact increases the normal grinding force and the grinding temperature. Advances in analysis of contact behaviour allow contact length to be reasonably estimated where widely used approximations are totally inaccurate. Practical grinding behaviour cannot be sensibly explained ignoring contact deflections. The importance of contact area and contact length are explained in simple terms and methods of calculation presented with numerical examples. References are given to previously published work.