High Precision Tool Cutting Edge Monitoring Using Laser Diffraction for On-Machine Measurement

The Far-field laser diffraction is proposed for measuring tool cutting-edges geometry with sub-micrometer precision. In particular, by eliciting an optical diffraction phenomenon, the cutting-edge of the tool can be monitored without a diffraction limit. This method can also be applied for on-machine measurements because of the simplicity and long working distance of the optical system; high precision can be achieved by using a laser light and there is no need for a vacuum environment. In this study, an on-machine tool measurement device using laser diffraction was developed to experimentally measure tool displacements of order of hundreds of nanometers; a piezo-drive stage was also used. Measurements of the cutting-edge curve of a ball endmill and a tool cutting-edge tolerance were also experimentally monitored.