| 摘要 |
PURPOSE:To detect an abnormality of a tool with a high degree of accuracy, by detecting an abnormal output voltage of a detector spaced at a predetermined distance from the surface to be worked, of a work made of electrically conductive material, for detecting eddy currents. CONSTITUTION:A work 5 is treated by a tool 2 so that a worked surface 51 is formed. A detector 3 is secured to a member suspended from a tool bed 1 with being spaced at a predetermined distance from the worked surface 52. In this condition, if the abovementioned spaced distance is constant and the surface roughness of the worked surface 51 is uniform, eddy currents are constant. However, if any abnormality is brought about in the tool, the eddy currents are varied, so that an abnormality judging signal is issued from a processing section. |
