bend allowance for odd shapes
bend allowance for odd shapes
(OP)
Any bending mavens out there know how to get the bend allowance for bending odd shapes like C-channel or angle iron?
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bend allowance for odd shapes
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RE: bend allowance for odd shapes
I've found that if you ask 10 different fab shops for their standard bend allowances for different materials you will get 12 different answers. Is this something you can come up with by trial and error?
RE: bend allowance for odd shapes
RE: bend allowance for odd shapes
The only problem is that when you ask a shop what bend radius they use, you'll _always_ get a wrong answer. You have to go out and measure the actual radius they achieve on a representative part.
I hate that whole 'bend allowance' fantasy.
Mike Halloran
Pembroke Pines, FL, USA
RE: bend allowance for odd shapes
If you have access to the shop where the work is to be done,
Shear a sample of metal, take it to the brake and bend it,
Measure the result and correct accordingly. This way you will be sure you have the correct radius and bend allowance
B.E.
RE: bend allowance for odd shapes
A good rule of thumb for bend allowances on a 90 deg bend are as follows:
thk<14GA BA=1.57(r+1/3t)r=male die rad
thk>15Ga BA=1.57(+.4t)
RE: bend allowance for odd shapes
thk<14GA BA=1.57(r+2/5t)
RE: bend allowance for odd shapes
These all make a difference. Go to the Fab Shop and ask. If you need something special, pay for a few samples.
RE: bend allowance for odd shapes
RE: bend allowance for odd shapes
Am I right in assuming you are wanting to bend, extruded/pultruded/rolled channels and angles?
What material?
Are they structural or decorative?
What is the min radius required?
Are they being formed the "right" way or the "wrong" way
All these things will determine which processes will be used (Rolled or Draw-formed, hot or cold) and the allowances needed.
RE: bend allowance for odd shapes
Regards,
Mike
RE: bend allowance for odd shapes
RE: bend allowance for odd shapes
Depends on how "accurate" you need to be. If I needed to slam out a piece or two and was measuring with steel rules, etc., I'd feel pretty good about using the N.A allowance. You'd have to measure pretty carefuly to see any difference.
Regards,
Mike
RE: bend allowance for odd shapes
RE: bend allowance for odd shapes
this is a very accurate way of doing it.
RE: bend allowance for odd shapes
If I understand your post correctly, you do not want to bend a flat piece of sheet metal into a C-channel, you want to bend a straight C-channel instead similar to this:
bent c-channel
We used a section bender to bend angle and c-channels. Typically these are used to roll them into a circle but we bent the material by inserting it and moving the rolls up until we reached the desired angle.
Section bender sample
Sorry I cannot tell you the bend deductions because it will depend on the machine you use to bend it.
Flores
RE: bend allowance for odd shapes
RE: bend allowance for odd shapes
"polyline along the neutral axis in AutoCAD"
Thank you
RE: bend allowance for odd shapes
If a polyline is created on the neutral axis (often along the mid-thickness of the material) it can be measured to give a close approximation of the flattened length.
RE: bend allowance for odd shapes
The subtle variation in some cad packages is to calculate the profile length for a section. Subtract twice the thickness, then divide by 2 and hey presto!
KENAT, probably the least qualified checker you'll ever meet...
RE: bend allowance for odd shapes
Bendworks
k-factor formula and tips
Flores
RE: bend allowance for odd shapes
RE: bend allowance for odd shapes
Flores
RE: bend allowance for odd shapes
The program is bendworks
http://www.ciri.org.nz/bendworks/
a super simple program for determining bend deductions,k factors,etc..
There is a nice part in the tools menu for reverse engineer k factor that I use all the time to get the right blank size for all press brake formed materials
RE: bend allowance for odd shapes
RE: bend allowance for odd shapes
4 breaks on 18 GA. C.R.S., I would not be impressed, BUT 4 breaks on 1/2" plate is very impressive.
Flores