GRINDING METHOD AND DEVICE THEREFOR

PURPOSE:To shorten idle grinding time in the process of a grinding wheel approaching a workpiece by detecting a space between the grinding face of the grinding wheel and the ground face of the workpiece directly in the contactless state. CONSTITUTION:When a grinding wheel 1 is rotated to start a grinding cycle in the state of a workpiece 2 being held in a grinding position, a wheel spindle stock advances rapidly. Meanwhile, the workpiece starts rotating, and the covers 6, 7 of a light projector 3 and a light receiver 4 provided at a contactless detector 5 are opened on both light projecting side and light receiving side. When a space between the grinding wheel 1 and the workpiece 2 then reaches a specific value, the change of light quantity emitted from the light projector 3 and received by the light receiver 4 is detected by the light receiver 4. This detection signal is inputted to a control device, and the feed speed of the grinding wheel 1 fed by a servo motor is changed to the grinding feed speed. At the same time, the covers 6, 7 of the light projector 3 and light receiver 4 of the contactless detector 5 are closed, and a grinding liquid valve is opened to start actual grinding from idle grinding.