Water driven stage was developed for use in the ultra-precision machine tools that is used for single-point diamond turning processes. A feature of the stage is that the size of the stage is small. Accordingly, the stage is advantageous for machining small precise parts in size. High bearing stiffness is needed for the performance of the ultra-precision machining. Even the size of machine tool is small, however, the bearing stiffness must be over acceptable level. A table of the stage is supported by water hydrostatic bearings. The stiflhess of the water hydrostatic bearings of the stage is thus considered via experiments and prediction using mathematical model. The experimental results show that the stiffness of the water hydrostatic bearing was approximately 34 N/μm if the supply water pressure is 0.4 MPa. Furthermore, it is indicated that the bearing stiffness can be 125 N/μm by the optimum design of the restrictor.
