20405 Measurement of bearing stiffness of spindle supported by water hydrostatic thrust bearings

A precision spindle used for ultra-precision machine tool is needed to produce precision molds for making various lenses or other precise parts. The machining accuracy required for the parts now reaches several tens of nanometers in some applications. In addition, the precision mold made of high-hardness materials is desired to improve machining efficiency and the durability of the mold. In order to achieve the desired machining accuracy for the high-hardness materials, the precise spindle system with high-stiffness bearings is needed for the ultra-precision machine tools. This study considers thus a design of a spindle supported by high-stifmess water hydrostatic thrust bearings. The object of this study is to develop the spindle supported by water hydrostatic bearings of 1 kN/μm. The spindle supported by water hydrostatic thrust bearings was manufactured. This paper presents measurement of stiffness of the thrust bearing of the designed spindle.