Bend Allowance

[whymejc]

Does anyone have a bend allowance formula that will work for any sheet metal material regardless of thickness and radii ?

Thanks

Regards
Ed

 

[jyatteau]

whymejc,

This is a general formula that you can use sorry diagram would not paste.

BEND ALLOWANCE (BA):

1)90° Bend: L= (t/3+r1) 1.5708 Note: General rule for r1 less than or = to (t) use t/3, for r1 greater than or= to (t) use t/2.

2)Less Than 90° Bend: L= (t/3+r1) (.0175x n°) Note: General rule for 90° bend applies.

3)360° Barrel Bend: Neutral axis use t/2.

L= bend length in inches.
t= material thickness in inches.
r1= corner radius in iches.
n°= bend angle in decimal deg.
K1= constant for 90° bend.
K2= constant for less than 90° bend.

Regards J. Yatteau
E-mail: myatteau@rochester.rr.com

 

[whymejc]

Thanks J. Over the last 30 years I have worked in 3 sheet metal shops and each one of them used different formulas.I like to make a test bend.Until I was laid off recently I was programming an Amada Astro-100 robotic press brake and all the B.A's are in the software. Again thanks

Regards
Ed

 

I happen to have a handy software which is based on calculations and it works on varius materials..emailme if you need it. thanks juan.morales@mailcity.com

 

[Andros]

A handy reference that I have found invaluable because it also contains details on the minimum bend radius for common gauges of sheet material is the "ZEUS" precision data charts and reference tables for drawing office, toolroom and workshop, available as far as I am aware from most engineering stockists and also from some stationers and bookshops, (WH Smiths etc)for under five pounds. As well as sheet metal information this pocket sized book also contains as the title suggests a number of other useful tables and reference charts.
Andy