Sheetmetal Overbending

[ornerynorsk]

Hello All,

I do not work with sheetmetal too much, but I know there are a good number of people who can answer my question in a practical way. I need to build a U-form die for bending a 14 gauge Grade 50 steel channel, 1.5 inch inside radius,equal legs, each leg being open from 90 by 5 degrees (not quite a square bend. Anyone have an answer for me on how much I need to overbend? Tolerance is +/- 1-1/2 degrees, so not terribly critical. I know this thing is going to have considerable springback, so I do not want to guess at it.

The channel legs are not deep, but the die needs to bottom out because of a formed boss feature on the bottom, so bending in air is not an option. This needs to be a 1 hit die.

Any comments would be appreciated.

 

[MikeHalloran]

I think you need to mock up the bend with the exact brand and grade of steel you propose to bend, then duplicate the mockup's punch radius as well as you can in the real tool.

Better, make the real tool adjustable; you will need different overbend for different heats.



Mike Halloran
Pembroke Pines, FL, USA

 

[ornerynorsk]

Thanks Mike, that's the conclusion we came to as well. we did a test die to get us close and went from there.