folding a box section

[WelderMick]

Hi all, I've been lurking over in the welding forum for a little while, but this is my first post here. I've got a question about folding sheet metal to form a box section at one end. I know it's relatively easy to fold a ' J ' section with 2 x 90 degree folds, but what about something that looks like a ' d ' ? See attached pic.

Is it possible to make a folding machine that will do this? For instance could the pan brake described in Simso's sticky (great thread by the way) be modified to do box sections?

thanks

- Mick

[rodm]

Hi Mick,
The problem is the bending fingers get in the way of the last bend. Only way I could do this is to hand form the last bend using a chunk of steel as a former inside the fold.

[joe greiner]

How about a press brake with an almost-square (with springback allowance) mandrel to form the lower left corner last? Might not work for a very long edge, due to flexibility of the mandrel.

Progressive roll forming, with judicious sequence planning, can also form some very strange shapes in longer or continuous material.

Cheers,
Joe

[Camoco]

Depending on the size and thickness of your material, you can bend all the folds with the last one being the one on the long edge. With this, take it as far as your equipment allows, then you need to press the long edge bend from the outside. Basically squashing them together, without over doing it. Hopefully you will then stitch the join by welding.

It may still spring open a touch before welding, but other than that you can only use a roll forming system to achieve the result.
I sometimes use the fingers in the open position as a press, in the pan brake. It depends on the throat opening and your section size and the machines capabilities.
You may need to set a clamp bar to stop the material sliding forward if using that method.
Cheers Cam

[WelderMick]

Hi guys,

The initial project is to make up a fish box/seat/console for the boat. The material I'm looking at is 1.6 mm aluminium. The maximum fold length would be about 590mm. The dimension of the box section isn't critical, but I was thinking in the order of 25x25mm. I could just weld some square section to the flat stuff, but was wondering if there was a more elegant solution using a folder. I think a roll forming setup is out of my league but was keen to make up a pan brake if there was some way to make that work. Cheers - Mick