Sandia ultrasonic aluminum welding research

Sandia's variable-pressure radiused-sonotrode technique that sweeps aluminum oxide outward in a circular wave to achieve 100% area of contact. Probably developed for a nuclear warhead application; contrasted with Ford's partial-contact approach.

They actually decided one time to do ultrasonic welding of aluminum. I have no idea what the application was. They took two sheets of aluminum and they put the sonotrodes — these are called sonotrodes, your ultrasonic welding tips. They made a huge radius on it — I can't even draw it as flat as it should be — but this was your big copper tip. There's another one down here. They would vibrate these things side to side, but they would vary the pressure coming in. As they did that they would first clean off just the center, because that's where the contact was. As they continued to press it in — this was on thin material, with about a four-foot radius on this hemisphere. To you it looked flat. But that was flat with a big radius. They would increase the pressure as they're vibrating, and they would take that aluminum oxide and push it out in a circular wave. So they got 100 percent area of contact, as opposed to what Ford does.