Figure error control for diamond turning by in-process measurement

This paper presents a technique to improve the turning accuracy or to control the cutting errors by in-process measurement. Newly developed “half-line Hartmann test” was applied as an in-process figure measurement for concave mirror cutting experiment. Since the datums of this turning control is in the figure measuring system, machine tool errors and environmental disturbances, primarily, do not influence the final figure error of the turned mirror. The results of experiment as well as computer simulation showed clear reduction of figure errors and confirmed a possibility of turning error correction.