Ultrasonic welding is a solid phase welding technique and has been used in the manufacture of automotive parts, such as relays. Typically copper wire is attached to copper or aluminium leadframes. Ultrasonic welding results in low heat conduction into the bulk material and the resultant robustness of the final joint can impart better joint integrity to external factors such as vibration loading than by making a crimp joint. The benefits of using ultrasonic welding include cost as well as good joint quality.