Abstract
A single point diamond turning (SPDT) facility is utilized for the ultra-precision machining of planar surfaces, and aspheric mirror components for geo-orbital x-ray telescopes and x-ray microscopes. The spindle of the machine tool is encased in an ultra-precision hydraulic bearing, and the motion controller is programmable to nanometer resolution. The radii of diamond cutting tools, utilized in the SPDT process, approach nanometer accuracy. This combination of parameters produces planar and aspheric components with nanometer surface and shape quality. We examine the radial and axial motion of the spindle in the static and dynamic domains with an optical nanometer-resolution sensor. The sensing geometry is based on standard optical triangulation off the target surface, and the sensor can be calibrated in situ utilizing the position controller of the machine. We present results, which examine the parametric performance of the diamond turning operation. At 1000rpm we measured a minimum of approximately 35-nm rms radial and the axial spindle error motion.
