Basically everything has been covered except I add a manual trim from the 3 way corner hole. You have to be careful to not violate a few rules. The hole in the 3 way corner must extend past the plasic zone. The connection from the slot to the hole can also be tricky. Many combinations of condition will make the flat pattern fail. Without a slot, the folder will cuss you out because there will be no way to deal with the spring back.
Lost me there...I guess thats where I lack in sheet metal design...I do not know all of the rules and such. So there needs to be a gap there? Why does SE not allow you to vary the gap between. Its either closed or open, but Ive seen no way to adjust the gap at a corner like this.
Typically the last bend is the one that makes the sides of the slot close. When bending sheet metal, for carbon steel, a 90 deg bend is typically bent about 94 deg, and the metal springs back 4 deg (stainless more, aluminum less). I manually cutout the slot.
I'm in process of working with GTAC to get exactly that enhancement.