stock here: I was surprised at the number of Patents on Vibrational Metal Processing……
https://duckduckgo.com/?t=ffab&q=patent+for+vibrational+welding&atb=v343-1&ia=web
And here is high frequency welding….
https://duckduckgo.com/?q=patent+for+frequency+welding&t=ffab&atb=v343-1&ia=web
And here is a focus on “Wave Form”
https://duckduckgo.com/?q=patent+for+frequency+%22wave+form%22+welding&t=ffab&atb=v343-1&ia=web