The static performance of the high-speed aerostatic spindles with modified discharge coefficients

Abstract

With the demand of the larger cutting forces and the more precise prediction of the performance of the spindle, the angular stiffness of the ultra-high-speed spindle should be taken into consideration. In this article, a 5-degree-of-freedom model of the aerostatic spindle is established by considering the one set of the thrust bearing and journal bearing together with the modified discharge coefficients in high-speed condition. Furthermore, static characteristics including angular stiffness of the high-speed aerostatic spindle are obtained in terms of different angular displacements and different operational parameters. The angular displacement effects are revealed and the optimum air film thickness for both thrust gas bearings and journal gas bearings is given for ultra-high aerostatic spindle design.