Ceramic Spindle Research Articles

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.

High-Efficiency and Precision Grinding Technology of HIPSN All-Ceramic Bearing Race

This paper deals with the development of a high-efficiency and precision grinding technology for producing HIPSN ceramic bearing races. A new high-speed CNC grinding machine has been developed, which is equipped with a high-speed ceramic spindle with a built-in motor. Extensive experiments have been performed with this new machine to investigate the influence of various process parameters such as wheel speed, work speed, depth of cut, and wheel grit size on material removal rate, surface finish, grinding forces, and so on. The results of these investigations are presented in this paper. With the application of this technology, a low cost production of ceramic bearings race was realized with the most optimized process parameter.

Viscometer for Lead Blast Furnace Slags

ONE OF THE AUTHORS recently described a rotating-spindle viscometer which was used to examine the relative fluxing effects of several additives for openhearth steel-making slags(l). A particular feature of this instrument was the use of slip-cast ceramic spindles. Compared to spindles of refractory or rare metals, these resisted the attack of the highly oxidized slags for a time sufficient to allow useful measurements to be obtained. Such spindles are also inexpensive enough to be discarded after one use. Subsequently, it appeared that similar viscosity measurements might aid in investigating the nature of lead blast furnace slags. Our limited objective was to assess whether it might be useful and practical to measure viscosity as a routine industrial practice. It must be emphasized that we did not envisage carrying out precision viscosity determinations under very carefully controlled conditions of atmosphere and temperature, such as those described recently(2H3).For this work, we incorporated a thermocouple within the hollow, disposable, ceramic spindle, thus allowing the viscosity-temperature curve to be measured by a single immersion device.