Making a Top Hat Section on a Pan Folder

[OJCar]

A friend has a Pan Folder machine.
I need some Top Hat Section folding out of 1mm Zintec 1.2 metres long

We are struggling to see how to sequence the folds.
(Probably missing the bleeding obvious ... )

How should we do it with the available folder?

 

[8ob]

Cant see a problem with that, bend the two 20mm legs down first to form a U section and then bend the 10mm edge upwards.

Bob

 

[piman]

Hello Ojcar,

if it's a conventional folder I think you can only do three of the four folds. the limiting factor is the width of the moveable section. E.g. if it 100 mm wide then the section you fold must be that dimension or greater. A press brake is more flexible from that point of view.

If some one knows better I'd love to hear how as I have the same conundrum from time to time.

Alec

 

[hotponyshoes]

If the bends are A-D from left to right,
And the strip is about 70mm wide,
Put 60mm into the folder and fold up A
Take it out, turn it over, put 50mm in and fold up B.
Pull it out 30mm and fold up C
Take it out, turn it over, put 10mm in and fold up D.

 

[hotponyshoes]

Ps, do a test piece first as you will need to allow a mm or so for each bend which you will have to add on for A & B and subtract for C & D.
(I think??)
Make a test strip with a few 1mm spaced lines on it first!

 

[droopsnoot]

When I was doing stuff like this in my folder, I made a top bar out of some square box section which was narrow enough because the one that came with it is too wide.

 

[Tupers]

I missed on in the middle here but I basically went inside - outside - inside - outside although my folder isn’t a box/pan one.

Depending on how steep the fingers on your friends box/pan folder are you should be able to do inside - inside - outside - outside.

 

[droopsnoot]

Oh. that's a nice folder- the fixed piece on mine is much wider and gets in the way of stuff like this.

 

[Tupers]

Oh. that's a nice folder- the fixed piece on mine is much wider and gets in the way of stuff like this.

This one has a piece of flat bar that bolts in flush with the rest of the lower section when you need to get very close to the clamp and you can also bolt in a section of angle to support large sheets but I’ve never needed it.

I would like to cut the upper section off at some point and fit fingers but I’d have to get them made first!

 

[rustylandrovers]

Cant see a problem with that, bend the two 20mm legs down first to form a U section and then bend the 10mm edge upwards.

Bob

The issue is that one you have folded the 'U' section, you can't then clamp it back in the folder because one or other of the bed/top bar/swingarm would be in the way. Different machines will have different geometry limitations, but the one in question is like this:

if it's a conventional folder I think you can only do three of the four folds. the limiting factor is the width of the moveable section. E.g. if it 100 mm wide then the section you fold must be that dimension or greater. A press brake is more flexible from that point of view.

If some one knows better I'd love to hear how as I have the same conundrum from time to time.

This was my thinking too. I've had to borrow the use of a press brake with gooseneck tooling in the past to do similar jobs (save for small lengths where I can do 3 bends as you describe, then the final 'bend' in the bead roller).

It's all good though, I can confirm that this is the case:

(Probably missing the bleeding obvious ... )

...because Tupers nailed the solution in one. Complete 'Duh' moment from me, but I'd never considered that the swingarm is two-piece (I mean I knew it was made that way, but I hadn't considered splitting it down to reduce the amount of it sticking out for tight jobs). If I unbolt and remove the angle section:

...I'll be left with just a 1/2" thick plate section, which will work similarly to Tupers' pics. You can see the split at the end of the ruler:

It'll not be perfect, as it will need a slight prebend in it as I clamp the material down, but (pending the final dimensions from OJCar) I should manage it. Handy tip, cheers Tupers!

 

[OJCar]

Told you we were missing something ...

( A responsible Adult mainly!)

 

[OJCar]

Two Off please.

 

[rustylandrovers]

I hate to be that guy who just takes the advice and runs, so here's a wee update.

It took a few goes to get this right; the final bend is tricky as it starts as the sheet is clamped under the top bar. Bends #1 and #3 had to be over-bent slightly to compensate for being un-bent at this point.

The final shape isn't perfect because of that final bend, but for this application (stiffener inside a wing) I'm sure it'll be fine.

This is 1.2mm zintec by the way (not 1mm as stated in original post - I must have got my wires crossed). My bender is rated at 80" of 16 gauge (1.6mm ish), but I wouldn't like to try that last bend in anything thicker than the 1.2mm.

Summary: if you want top hat section, a box folder will work, but it's not the best tool for the job. If I were regularly doing these shapes I'd be looking for a press brake! I can see it being handy though - a quick (ish) way of making the aluminium top hat sections to go under land rover tub floors has previously eluded me.

 

[droopsnoot]

If I were regularly doing these shapes I'd be looking for a press brake!

I do make this shape quite regularly, the way I solved it was to take the profile to a local fabrication company and they bent up some lengths for me, at a very reasonable price.