Study of variable depth air pockets on air spindle vibrations in ultra-precision machine tools

The low vibration of air spindle is a very important thing to achieve nanometer accuracies in the products of machined parts in nano-machining. Compared to the common air pockets with constant depth used in air cells of ultra-precision machines, this paper studied some special air pockets including five variable depth modes: flat, conical, pyramidical, spherical with two sphere radii. Considering rotational speed as well as these parameters, 18 experiments have been committed using a lathe machine. From experiment results, the air spindle with air pockets of pyramidical depth at a low rotational speed has minimum vibrations.