If you want to form a piece of sheet metal into a shape, you’ll probably think about using a die. That’s certainly a great way to do it, but it presupposes you can create or purchase the die, which may be a showstopper for small projects. [Dardy-7] has worked out how to use a lesser-used technique — incremental sheet forming — to get similar results with a CNC machine. The idea is to trace out the form on the sheet metal with a round blunt tool.
He got good results using an inexpensive dapping tool, although he’s seen other use heated titanium ball bearings. In addition, he’s worked out how to adapt existing tool paths, like the ones you might download from the Internet, to use with this technique. You can see a video of the workflow below.