Abstract: Resistance welding has long been used in both the aerospace and automotive industries for welding aluminum sheet. Generally, the process is challenged by very high power demands and concerns over electrode wear. More recently, ultrasonic spot welding has also been investigated for these materials. While promising, limited ultrasonic power, long cycle times, and surface indentation have reduced the attractiveness of this approach. This paper addresses combining these approaches into a new hybrid system. A prototype system was developed and used to weld aluminum 6061 to itself. Welds with high lap shear strengths were achieved compared to those made with ultrasonic power alone. This increase appears due to local resistive heating, reducing the yield strength at the faying surfaces. Reduced yield strength allows additional plastic deformation by the sonotrode into the material permitting ultrasonic motion to be achieved at the interface more efficiently.
Authors: Lindsey Lindamood, David Workman, and Jerry Gould
Keywords: ultrasonic welding, resistance spot welding, hybrid spot welding, aluminum, lightweight, automotive