PVD Film Method for Measuring Grinding Temperature

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The near-surface temperature distribution in the workpiece in surface grinding was measured by applying the PVD film method developed recently. In this technique, the workpiece is parted into the two parts same in size in the direction parallel to the grinding direction. Then the inner surfaces of the both parts are ground and lapped to mirror surface. The two parts are fastened together and ground after the material with a definite melting point is vapor-deposited on the inner surfaces. When the interface is observed by a microscope after the grinding test, the boundary between the melted film zone caused by grinding heat and the unmelted film zone on the interface is positively identified. The temperature of the workpiece on the boundary can be expected to agree with the melting point of the deposited film material. If the same experiment is repeated by using various PVD films of different melting points, the temperature distribution of the near-surface of the workpiece in the depthwise direction can be estimated accurately.The influence of the grinding condition, the work material and the grinding wheel material on the temperature distribution was investigated under a conventional surface grinding. The conclusions obtained are as follows.(1)It was shown experimentally that the temperature gradient at the near-surface is in good agreement with Takazawa's approximation based on Jaeger's moving heat source theory. It depends on only the thermal diffusivity of the work' the wotk speed and the wheel-work contact length.(2)Energy partition coefficient, calculated with the extrapolated maximum temperature rise at the surface, changed from 0.5 to 0.9, depending on the grinding conditions, the work material and the wheel material.(3)The temperature measuring technique outlined in this paper seems to be a promising method in the field of grinding research.