Precision Prediction Model and Experimental Verification of Hydrostatic Bearing-Rotor System of Ultra-Precision Machine Tools

Error averaging effect of the pressured oil film allows for a high motion precision in hydrostatic bearings. This has many applications to ultra-precision machine tools rotor-bearing system. This paper mainly focuses on the studying factors affecting the rotor-bearing system error for hydrostatic rotation table and hydrostatic spindle in ultra-precision grinding machine. Radial run-out error was selected as precision evaluation index. A precision prediction model was established, which takes into structural and dynamic parameters of hydrostatic radial bearing rotor-bearing system into consideration. Effect of assembly tolerance, structural parameters and working conditions on the accuracy of the rotor-bearing system were analyzed. Precision measurements for the ultra-precision hydrostatic rotary table and spindle were carried out. Prediction errors of radial run-out error was found to be less than 23.5%. The model proposed in this paper has high prediction precision and can be used to guide the precision design and optimization of the ultra-precision machine tools rotor-bearing system.