Development of aerostatically lubricated table system.

An aerostatically lubricated table system, which is free from oil contamination, was developed to enable ultraprecise movements. Including the read screw system, all relative sliding parts of the table system are aerostatically lubricated. Static stiffness of the table system and accuracy of the table movement are experimentally investigated. The measured static stiffness of the table system is 8 N/MUm in the feed direction, and 160 N/MUm in the vertical direction. Positioning error of the table, which was measured with a laser interferometer, does not exceed 70 nm. Because of the extremely low frictional resistance of the aerostatically lubricated elements the movement of the table system is completely free from backlash. Consequently, it was confirmed that the aerostatically lubricated table system developed was capable of achieving very smooth and accurate movements. (from authors' abstract)