Design of carbon fiber composite shafts for high speed air spindles

For the stable operation of high speed air spindles, the low rotational inertia and high damping ratio of spindle shafts as well as high fundamental natural frequency are indispensable. Conventional steel spindles are not appropriate for high speed operation because of their high rotational inertia and low damping ratio. In this study, a high-speed air spindle composed of a carbon fiber epoxy composite shaft and two steel flanges was designed for maximum critical speed considering both the deflection due to bending load and the radial expansion due to centrifugal force and temperature rise during high-speed rotation. The stacking angle and thickness of the composite shaft and the adherend dimensions of the steel flanges were selected through vibrational analysis as well as considering the bending stiffness and centrifugal characteristics.