Optimization of ultrasonic welding parameters for copper to copper joints using design of experiments

Ultrasonic welding is a solid-state joining process that produces joints by the application of high-frequency vibratory energy in the work pieces held together under pressure without melting. In electronic and automotive applications, copper wires are connected to the equipment (alternator/rectifier) by a solid state joining process. For such an application ultrasonic metal welding is useful. The dominant problem faced by industry dealing with ultrasonic metal welding process is the poor weld quality and strength of the weld due to improper selection of weld parameters. In this work welding parameters like welding pressure, weld time and amplitude of the vibration are considered while producing ultrasonically welded joints of copper whose thickness is 0.2 mm. If other modes of joining are used, this size being very small, it may damage the weld. A suitable experimental design based on Taguchi’s robust design methodology was designed and executed for conducting trials. The analysis of variance (ANOVA) and signal to noise ratio analyses are employed to investigate the influence of different welding parameters on the weld strength and to obtain the optimum parameters.