Ultrasonic assisted dry grinding of 42CrMo4

In recent years, many cooling lubricants are classified as health hazards, while their end-of-life treatment poses numerous ecological threats. Dry machining is a solution for greener production and also is a favorable process from an economical point of view. However, compared to other machining processes, conventional grinding has a low material removal rate and involves high specific energy. A major part of the specific energy in grinding is changed to heat that makes harmful effect on surface quality. Therefore, in conventional dry grinding, as there are no cutting fluids to transfer the heat from the contact zone, the temperature of workpiece surface and grinding wheel surface will be increased resulted to thermal damage and poor surface integrity, increasing of wheel wear and inefficient grinding compared to conventional grinding. To make a step forward to pure dry grinding and to eliminate the negative environmental impact of the cutting fluids, a new technique called ultrasonic assisted dry grinding has been used. The advantages of ultrasonic assisted grinding were proved mostly for the brittle material. Our investigations show the improvement on the surface roughness, considerable reduction of the normal grinding force, and thermal damage in case of using ultrasonic assisted dry grinding compared to conventional dry grinding for a soft material, 42CrMo4. A decrease of up to 60% of normal grinding forces has been achieved.