Development of an ultrasonic elliptic-vibration shoe centerless grinding technique

Abstract This paper describes the development of a new centerless grinding technique called the ultrasonic elliptic-vibration shoe centerless grinding. This new method employs an ultrasonic elliptic-vibration shoe to support the workpiece and control the workpiece rotational motion instead of using a regulating wheel such as that employed in conventional centerless grinding. First, an experimental apparatus is established by designing and producing an ultrasonic elliptic-vibration shoe and a fine feed mechanism, and then attaching them on a conventional centerless grinder which is commercially available. Next, in order to clarify the performance of the constructed equipment, the elliptic motion of the shoe-end-face is investigated using laser vibrometers, in addition to workpiece rotational motion control tests under a grinding-like configuration. Finally, in order to confirm the validity of the new method and to determine the optimum geometrical arrangement of the shoe, grinding experiments involving pin-shaped workpieces with an initial roundness of 25 μm are conducted on the established equipment for various values of the shoe tilt angle γ. The results obtained indicated that the roundness improved for any values of γ, and that γ=7° gave the minimum roundness error, confirming the validity of this technique.