Bend Allowance = 0

[Belgium]

Hello,

I've got a problem with sheet metal.
We've done a lot of tests in our factory concerning the material you have to add or loose when you bent a sheet metal plate.
Our results show that for 0.8mm plate we have 0mm material we have to add. Now in SW you can't give a bent allowance of 0mm , the smallest is 0.01mm. Is there an easy way to use 0mm ??

Thanks,

 

[YJeepster]

Belgium,

I am assuming you are using 20GA CRS sheet stock. Are you air bending? If so what radius punch, and what size "V" openning?

Are you talking true BA or an OBD (Outside Bend Deduction)?

What about using a K-Factor insted of a BA in SW?

Geoff

 

[Belgium]

I don't know what you mean by 20GA CRS sheet stock but we are air bending and flat (bend), the punch radius is 0.8mm and the V-size openning = 14mm.
I'm not that familiar with BA OBD and K-factor (untill we start using SW we just used our experience, But now we have to start using BA, OBD or K-factor.
Untill someone tells me an easy way to become 0mm I use an internal radius of 0mm so that my BA = 0.01mm for every angle I create in SW (I think that upon one point I'm getting problems with this but untill than I'm using this rule).
If someone can give me advice , thanks.

 

[Arlin]

Using k factor = 0.5 should get you what you want.

 

[rocheey]

I 'reverse engineered' a K-Factor of .28 to return NO allowance.

 

[Htaed]

I've wriiten a program for figuring BA and press brake set back. The formulas used in it are taken from over 10 years experience in the metal fabrication industry. It is used in the plant I work for and the engineers there found it very useful. If anyone is interested in it please let me know. I'd be happy to share.

htaed@comcast.net