Designing of Ultrasonic Horns to Improve Amplitude Uniformity in Ultrasonic Metal Welding

Abstract

The ultrasonic metal welding has been used extensively in many fields because it can weld thin layers of highly conductive and dissimilar materials with high reliability. In particular, one-wave length horns with four welding tips on both sides of the horn are widely used for welding positive and negative electrodes and tabs of rechargeable lithium ion batteries. As the vibrational amplitude of each tip is known to be non-uniform, this causes some problems in welding performance. In this study, the one-wave length horn which has four welding tips on both sides of the horn is newly designed to improve amplitude uniformity of each tip. The design of experiment technique is employed to determine the optimum configuration of the horn. The modal analysis and harmonic response analysis are repeatedly conducted to obtain the uniform amplitude of horn tips, and stress distribution in the horn is analyzed finally. It is shown that the uniformity of amplitude can be improved by making appropriate grooves on both sides of the conventional horn.