Self-evaluation of the cutting edge contour of a microdiamond tool with a force sensor integrated fast tool servo on an ultra-precision lathe

Abstract

This paper presents a self-evaluation method for sub-micrometer accuracy measurement of the cutting edge contour of a micro diamond tool with a force sensor-integrated fast tool servo (FS-FTS) on an ultra-precision lathe without using any accurate reference artifacts and additional surface form measuring instruments. At first, a series of grooves is cut side by side along the Z-direction over the outer surface of a cylindrical artifact mounted on the lathe spindle by the micro tool of the FS-FTS, which is mounted on the X-directional cross-slide (X-slide) of the lathe, to form a number of sharp line structures. The FS-FTS is then switched to a force feedback control mode for the cutting edge of the micro tool to scan across the line structures as a measuring stylus by moving the artifact with the Z-directional carriage slide (Z-slide) of the spindle. During the scanning, the contact force between the micro tool and the line structures is maintained constant by controlling the X-directional displacement of the cutting tool with the FS-FTS so that the tool cutting edge contour can be obtained from the tool scan trace profile provided by the linear encoder of the Z-slide and the displacement sensor of the FS-FTS. Measurement experiments of a micro tool with a nominal nose radius of 120 μm are carried out to demonstrate the feasibility of the proposed method.