I have a sheet metal cone made using a lofted bend, it's got a slight taper on it.

I need to unfold it, add tabs for spot welding, and then fold it and create a flat pattern. 

I can unfold the part, but I can't fold it back even with no changes made. 

I've done this dozens of times on straight collars, I'm out of ideas on how to make this work with the taper. 

any ideas on how to move forward with this? 

EDITED BY MODERATOR: Moved to the Sheet Metal sub-space. Please post to the appropriate sub-space when one exists.