New machining method of a large-size asymmetric aspheric mirror

Abstract A high precision diamond cutting machine has been developed for fabrication of a large size asymmetric aspheric mirror for soft X-ray optics. It is based on the positioning function of a diamond tool in the cylindrical coordinate. Error motions of slide table in Z-axis is adjusted by the radius R and the rotatingangle B. A workpiece fixed on an air bearing table can go and return with such a high accuracy of 0.05 imin straightness covering 600 mm stroke. The tool position in radius direction is controlled better than 0.01 m by a DC servo motor and a piezo-actuater and that in rotating direction is controlled better than i07radian using only a DC servo motor. So, any radius in a cross section of a large size mirror, which is perpendicular to the rotating axis can be machined with these precisions. This new machining method has an advantage to decrease a scattering light because the direction of cutting is the same as the incident direction of light. The machining design and the features of the system are briefly reported.