Figuring with subnanometer-level accuracy by numerically controlled elastic emission machining

A numerically controlled elastic emission machining (EEM) system has been developed to fabricate ultraprecise optical components, particularly in x-ray optics. Nozzle-type EEM heads, by which a high shear-rate flow of ultrapure water can be generated on the work surface, have been newly proposed to transport the fine powder particles to the processing surface. Using this type of EEM head, the obtainable spatial resolution in figure correction can be changed by selecting the suitable aperture size of the nozzle according to the required spatial frequency. As a result of test figuring, 1 nm level peak-to-valley (p-v) accuracy is achieved throughout the entire spatial wavelength range longer than 0.3 mm. In addition, the microroughness of the processed surface is certified to also be approximately 1 nm (p-v). (C) 2002 American Institute of Physics.