Monitoring of distance between diamond tool edge and workpiece surface in ultraprecision cutting using evanescent light

The interaction between a tool and a workpiece during machining determines the quality of a machined workpiece. This study presents a novel direct monitoring method using evanescent light, which detects the distance between a diamond tool edge and the workpiece surface. In the proposed method, evanescent light is generated around the diamond tool edge, and the intensity of the reflected laser beam corresponds to the distance between the tool edge and the workpiece surface. Experimental results confirmed that the proposed method is capable of monitoring the distance change of a sub-micrometer scale.