Here’s a quick tip for folding sheet metal – If multiple returns are needed on a sheet metal pressing, make each return twice as long as the previous one as shown in the example picture. This allows good clearance between the blade and the return as folding is progressed.
With experience and tooling such as a joggled blade this ratio can be reduced somewhat, but designing components to be made as simply as possible is always good practice.
“Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius – and a lot of courage – to move in the opposite direction.” (E.F Schumacher)