Ultrasonic metal welding by longitudinal-torsional vibration source consisting of two transducers

We study ultrasonic metal welding of dissimilar metals by using planar vibration locus. The planar vibration locus consists of the longitudinal vibration and the torsional vibration. In a previous study, we used an ultrasonic vibration source that contained a vibration converter comprising diagonal slits. The vibration source with diagonal slits was driven two frequencies in order to obtain a planar vibration locus. However, it was difficult to control individual vibration when using the vibration source with diagonal slits. In order to solve this problem, we have developed an ultrasonic longitudinal-torsional vibration source consisting of two transducers in which the longitudinal-torsional vibration can be controlled. The developed vibration source is consists of a longitudinal transducer and a torsional transducer attached to the both ends of a stepped horn with the length of two wavelength of the propagating vibration. This vibration source can generate planar vibration locus of substantially square. In this study, ultrasonic metal welding of dissimilar metals was studied by using the vibration source consisting of two transducers. As a result, high weld strength was obtained in the case of welding of the planar locus than welding of only longitudinal or torsional vibration loci.