A New Approach to Development of a Grinding Force Model

A theoretical model has been developed for representing the grinding forces. This is based on the fact that the chip formation during grinding consists of three states: ploughing, cutting, and rubbing. Expressions for the total normal and tangential force components during these three stages were established. These components were expressed in terms of the chip thickness coefficient, the friction coefficient between the grit tip area and the workpiece, the stress coefficient arising during ploughing and, finally, the loading coefficient. The latter is expressed as an exponential in time. All these coefficients were determined experimentally by performing normal grinding tests at specified configurations. During these tests the forces were measured simultaneously with the loaded area on the grinding wheel during the process of grinding. The loaded area on the wheel surface was measured by a new technique using fiber-optics. This is based on the measurement of the reflectivity of the loaded particles. This system was calibrated by high magnification photographs taken of the surface texture. The predicted normal and tangential forces during the grinding process were compared with those experimentally obtained during the grinding tests mentioned earlier, showing reasonable agreement, both quantitatively and qualitatively.