Development of an ultra-precision machine tool

1st report:Improvement of performance of an aerostatic bearing spindle with an annular restrictor

Abstract

This study clarified the characteristics regarding the rigidity, accuracy, heat generation, etc., of aerostatic bearing spindles. Type A and B aerostatic bearing spindles with annular restrictors were manufactured for the test, and the material of the bearings were made from a type of carbon. This paper presents methods for evaluation of run out and imbalance correction of the spindles. In addition, the optimum clearance for hole diameter of the restrictors and effects of balancing and thermal deformation for heat generation were examined by experiment. The results clarified the points where attention should be focused when aerostatic bearing spindles are applied to ultra-precision machine tools. Moreover, improvement of rigidity and reduction of air consumption of the spindles were confirmed by applying restrictors of smaller diameter (φ0.05 mm).