A non-contact system for the measurement of cutting edge angles of rotary tools

Relief angles and rake angles of end mills, reamers and thread taps are often formed by surfaces with a width of less than one millimeter. Sample inspection using a contour projector, which up to now has been applied in the manufacturing process of these tools, requires a destruction of the sample. This paper shows a non-contact and non-destructive method for measuring these angles. The technique features a directed illumination of these surfaces. An optical detector configuration is used to determine the direction of the reflected beam. This direction describes the angular position of the surface against the measuring system. The relation between coordinate system of the tool in the illuminated spot and the reference system of the optical measuring device is determined by a second setup. Both optical angle measurement and the determination of the coordinate systems lead to the measurement of the cutting edge angles. As for the example of an end mill the reproducibility attained amount s to about +- 0.1 degree. (IPT)