Development and Experimental Investigation of a High Speed Grinding Spindle Equipped with Fully-Ceramic Bearings and Ceramic Shaft
Trend of the high-speed and high efficiency machining has pushed the continuous demand of higher spindle speed and power for the machining center application. However, Conventional steel spindles are not appropriate for high speed operation because of their high rotational inertia and low damping ratio. Moreover, heat generation and dynamic loading caused by high speed rotation have been obstacles for increasing the speed limit in many conventional steel spindles applications. Apart from optimizing lubrication, the application of new materials is an interesting alternative to increase the boundary speed and life-span of roller bearings for machine-tool spindles. In this study, a high speed grinding motorized spindle equipped with hot isostatically pressed silicon nitride (HIPSN) fully-ceramic ball bearings without inner rings and yttria partially stabilized tetragonal zirconia polycrystal (Y-TZP) ceramic spindle shaft was designed for higher speed, rigidity, precision and longer operating life. Furthermore, the characteristics of ceramic motorized spindle, such as temperature increase, vibration, power, rigidity, noise and so on, were investigated by the experimentation. The results show that the ceramic motorized spindles have good behaviors under low load, high speed grinding conditions.