The required die width is 12 mm and tonnage per meter is 22. I can now see that the minimum flange length is 8.5 mm for such a bend, so I have to keep it in mind when designing. To keep it simple, I also use a 2 mm inside radius. Let’s say I have a 2 mm thick sheet and I want to bend it. The imperial version of the bending force chart can be found here The highlighted options are recommended specifications for metal bending. You can see that thicker materials and smaller inside radii require more force or tonnage. Each operation needs a certain tonnage per meter. You can also see the die width V (mm) that is needed for such specifications.
The bending force table below helps you identify the minimum flange length b (mm) and inside radii ir (mm) according to material thickness t (mm). Air bending and bottoming account for around 90% of all bending jobs. V-bending is the most common bending method using a punch and die. It has three subgroups – bottoming, air bending and coining. Simpler methods are more flexible and most importantly, need fewer different tools for getting a result. The dilemma is usually between going for accuracy or simplicity, while the latter gets more usage. There are quite a few different bending methods available.
