Miniature percussion welder - video

[BuffaloJohn]

I have never heard of this process before. So start a weld pool on one side, and slam another piece of material into it. What are the benefits to doing it this way?

https://en.wikipedia.org/wiki/Percussion_welding

"Percussion welding is used to join dissimilar metals together, or used when flash is not required at the joint. Percussion welding is used on materials that have small cross sectional areas.

Advantages of using percussion welding types include a shallow heat affected zone, and the time cycle involved is very short. Typical times can be found to be less than 16 milliseconds. "