Speculation on Ultrasonic-Assisted Grinding with an Engineered Wheel

The ability to perform high-quality, shear-mode grinding of brittle materials such as glass critically depends on an adequate flow of coolant through the contact zone between the tool and the workpiece. A long contact zone limits the induction of coolant and thereby promotes high temperatures in the contact zone where heat is generated. For workpiece materials like glass, the high temperature and subsequent quenching causes surface and subsurface damage. High temperature of the wheel also tends to promote faster wheel wear. In contrast, short contact lengths tend to reduce the temperature of both the workpiece and the wheel. For some grinding geometries, where a long contact length is difficult to avoid, an alternative is to excite the wheel at ultrasonic frequency, which also admits coolant between wheel and workpiece. Results are shown of grinding force with and without ultrasonic excitation and the analyses of the resultant surfaces.