Influence of ultrasonic vibrations on dry grinding of soft steel

Abstract

Dry machining has been increasingly investigated in order to decrease the negative environmental impact of the cutting fluids, diminishing problems concerning waste disposal demand and also due to interest in decreasing manufacturing costs. However, generally in dry grinding, as there are no cutting fluids to transfer the heat from the contact zone, problems frequently occur in terms of high heat generation on grinding wheel surface and workpiece surface, increasing the grinding energy, wear of grinding wheel, low material removal rate (regarding relatively low depth of cuts) as well as poor surface roughness compared to conventional grinding. A recent and promising method to overcome these technological constraints is the use of ultrasonic assistance, where high-frequency and low amplitude vibrations are superimposed on the movement of the workpiece. The design of an ultrasonically vibrated workpiece holder and the experimental investigation of ultrasonically assisted dry grinding of 100Cr6 are presented. The surface roughness and grinding forces of the ultrasonically and conventionally ground workpieces were measured and compared. The obtained results show that the application of ultrasonic vibration can eliminate the thermal damage on the workpiece, increase the G-ratio and decrease the grinding forces considerably. A decrease of up to 60–70% of normal grinding forces and up to 30–50% of tangential grinding forces has been achieved.