Study on non-contact chuck using ultrasonic vibration (on primary cause of holding force acting to a floating object)

It is experimentally known that a flat surface vibrating at ultrasonic frequencies generates forces in both vertical and parallel directions to a vibrating surface, and these forces can support a floating object without any contact. However, the cause of the force parallel to the vibrating surface (called a holding force in this paper) has not been clarified yet. Therefore, this paper investigates the cause of the parallel force generated by a vibrating surface, experimentally and numerically. In numerical calculations, computational fluid dynamics (CFD) was used in order to obtain the pressure distribution of air surrounding a floating object and a vibrating plate. It was consequently found that the holding force acting to a floating object is due to an average minus pressure generated at the edge of a floating object on the vibrating flat surface.