Optimisation of interrupted grinding parameters according to the temperature criterion

Abstract

In the paper analytical optimization of discontinuous grinding parameters according to temperature criterion is carried out and on its basis conditions for significant reduction of cutting temperature, which consist mainly in increasing the number of contacts of working ledges of discontinuous wheel with fixed cross-section of machined workpiece, are determined. It is established by calculations that providing 20 contacts the cutting temperature may be reduced up to 3 times in comparison with the conventional grinding by a continuous wheel. This is achieved in the conditions of deep interrupted grinding with relatively low workpiece speed, as in the conditions of traditionally used multipass interrupted grinding not more than 6 contacts of working ledges of an interrupted wheel with the fixed cross-section of the workpiece are realized and the cutting temperature is reduced only in the range of 50 %. It is established by calculations that the minimum of cutting temperature at discontinuous grinding is achieved under conditions of equality of lengths of the working shoulder and the notch on the discontinuous grinding wheel and their reduction. It is also established that excess of the length of the working ledge over the length of the notch of the discontinuous wheel leads to insignificant increase of the cutting temperature. This reduces the wear of the discontinuous wheel and increases the machining capacity without actually increasing the cutting temperature. The paper shows that the obtained theoretical solutions are a necessary condition for ensuring a significant reduction of cutting temperature in discontinuous grinding. A sufficient condition should be considered as complete or partial cooling of grinding zone between contacts of machined workpiece with working jaws of discontinuous grinding wheel by intensive supply of effective technological media into the grinding zone.