CERAMIC GRINDING TEMPERATURES

Workpiece and abrasive-tip temperatures are measured during the grinding of silicon nitride, zirconia, sapphire, and Ni-Zn ferrite with diamond abrasives. The measurements are carried out using a multiple-element infrared sensor having a time constant of approximately 7 mus and a spot size as small as 30 mum in diameter; the temperature measurements were made for both single-point and full-wheel grinding. A simple analytical model is used to predict the abrasive-tip and work-surface temperatures, the subsurface temperature of the workpiece, and the cooling of the abrasive grains between cutting. The predictions of the model agree reasonably well with experiments. The model requires as inputs only the grinding forces, grinding process variables, and the physical properties of the abrasive and workpiece materials. It is shown that, in view of the excellent thermal properties of the diamond abrasive, the surface temperature of the ceramic workpieces is essentially independent of the thermal properties of the ceramics.