Dynamical investigation of a wrap-around gas bearing design in a vacuum environment

Ultra precision positioning stages often use gas bearings to realize the sophisticated demands of positioning accuracy and repeatability which are required for tasks like wafer processing and inspection, e.g. for EUV lithography. One common method of realizing a linear guided structure with high stiffness is a wrap-around design of two or more thrust gas bearing pads. Since some of the processes have to be performed in a high vacuum environment, dynamic tests are carried out inside of a vacuum chamber. The influences of different input parameters (supply pressure, velocity) on the stability of the wrap-around design are investigated. The first results show that no self-excited vibrations occur at supply pressures up to 400 kPa and a maximum velocity of 80 mm/s.