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Join Date: Sep 2009
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# Sheet Metal Bending Calculations...help

04/02/2010 6:27 AM

Hi;

Recently i have been using CATIA as my 3D modelling tool for sheet metal designing.I am now experiencing problems in final manufacturing due to the development drawings created for sheet metal cutting & bending.For example I have to bend a sheet into L-Shape where its vertical Height is 928(top to floor) & horizontal Length is100mm(outside to outside).How much length(total length before bending) of sheet should i take to make this bend happen? Is there any formulae to calculate this.....

Thanks...

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Active Contributor

Join Date: Sep 2009
Posts: 23
#1

### Re: Sheet Metal Bending Calculations...help

04/03/2010 5:28 AM

Thats the problem frnd...I got a lot of answers.... but the thing is all are discrete in formulae & results...all answers differ at least by 0.1-0.3mm. I am using a complex system which has gaps in prts of abt 2-5mm.Hence it affects the whole assembly of system.

Guru

Join Date: Feb 2008
Location: Van Nuys, CA
Posts: 563
#2
In reply to #1

### Re: Sheet Metal Bending Calculations...help

04/03/2010 12:01 PM

"I am using a complex system which has gaps in prts of abt 2-5mm." is a long way from your original question, "I have to bend a sheet into L-Shape".

What exactly are you trying to accomplish? Precision sheet metal forming is more complicated than commonly assumed.

Guru

Join Date: Apr 2009
Location: Yellowstone Valley, in Big Sky Country
Posts: 7001
#4
In reply to #1

### Re: Sheet Metal Bending Calculations...help

04/05/2010 11:58 AM

I agree with pantaz and lynlynch: a simple 'L' shape (assume 90O) with 100 and 928 legs (leg dims really do not matter) should yield an error of no more than one thickness of the metal... if you are doing it wrong the correct way.

Have you remembered to always use stretchout dim from inside the brake line? Can you post a sketch of this 'complex system'?

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#5
In reply to #4

### Re: Sheet Metal Bending Calculations...help

04/06/2010 1:36 AM
Guru

Join Date: Apr 2009
Location: Yellowstone Valley, in Big Sky Country
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#6
In reply to #5

### Re: Sheet Metal Bending Calculations...help

04/06/2010 9:37 AM

Gee, I thought it might be a complicated shape!

The one shown here would be complicated to build!

On your drawing, there seems to be an inconsistent shape at the curved part... a 150O intersection with the 150O plane? Is this 1 piece in the flat, and broken on a box brake? Or are there a number of parts welded after shaping?

No matter... regarding your original plea for formulae: there are rules and guidelines applicable to the bending and shaping of metal. lynlynch gave you these in #1. Review your drawing, review these guidelines, and apply. Stretchouts are taken from inside the bend, and still apply to bends other than 90O.

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Guru

Join Date: Feb 2008
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Posts: 563
#7
In reply to #5

### Re: Sheet Metal Bending Calculations...help

04/06/2010 11:28 AM

According to that drawing, several features are physically impossible without subassemblies, and/or joined edges (i.e., welding).

Now show us the unfolded drawing with bend lines.

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#3

### Re: Sheet Metal Bending Calculations...help

04/03/2010 12:10 PM

Also,

It's hard enough to understand what you want without all the nonsensical abbreviations that could mean anything.This is an engineering site not a texting group.