Thrust air bearing has a merit of low friction under high rotating speed. On the other hand, the dynamic stiffness to the external excitation is considerably low compared to the stiffness of oil bearings. This has made it a problem for the air bearing to be widely used in the high precision machinery. Hashimoto et al. has discovered a modified spiral groove geometry through the optimization methodology. The modified spiral groove bearings have been proven through calculations to have a much higher stiffness compared to conventional spiral groove bearings. In this paper, a parametric study to investigate the importance of the groove geometry being accurately designed and manufactured was presented geometry. By changing the angles of the groove geometry from the desired, the bearing performance was examined. As a result, the effects of manufacturing accuracy in groove geometry were clarified.
