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Bending metal with a plasma cutter

edwin dirnbeck

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Joined
Oct 24, 2013
Location
st,louis mo
Here is a guy that made a nice five sided box by processing it on his plasma cutter and bending it by hand or in a Vice. I think you could use the same idea to band thicker metal by making multiple slots that were spaced correctly. The big advantage of this would be to fabricate things without any kind of fixturing or bending machinery. You could then simply weld up the edges where necessary to finish the project Edwin dirnbeck
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At the very back of the Lincoln Electric books "Design of Weldments"...is a statement
"Sometimes, the best weld is one you don't make"
 
It’s just gash bending that’s been done with an ASNM nozzle, thin cutting disk (more recent, I remember the first one I saw, I thought this looks like a face full of grinding wheel, how wrong I was)
However I’d not seen a plasma version, only laser, good thinking
Mark
 
It’s just gash bending that’s been done with an ASNM nozzle, thin cutting disk (more recent, I remember the first one I saw, I thought this looks like a face full of grinding wheel, how wrong I was)
However I’d not seen a plasma version, only laser, good thinking
Mark

Mark ,thanks for the thoughtful reply. Other have scoffed at this. I spent all of my career working in very well equipped tool and die job shops.We had very little sheet metal fabricating machinery.It was always a struggle to make a simple sheet metal guard. Edwin Dirnbeck
 
I have been doing this for 30 years, but on thicker material, you still need to use a brake. It does increase the capacity of your brake, but thicker than 16 gage, you need mechanical advantage. I have a friend who does amazing stainless steel sculptures this way, cad designs, laser cut, but hand bent. Heath Satow Sculpture - Portfolio
 
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I have been doing this for 30 years, but on thicker material, you still need to use a brake. It does increase the capacity of your brake, but thicker than 16 gage, ou need mechanical advantage. I have a friend who does amazing stainless steel sculptures this way, cad designs, laser cut, but hand bent. Heath Satow Sculpture - Portfolio

We did this on 3/16 before we had a brake. Worked fine, but your slot needs to be wide enough to account for the material compression, or you'll never get it bend by hand.
 
so let me get this straight, you weld with the plasma cutter? (i never used one.)
 
The technique is valuable when you have missing material that will lie inside the vee in a press brake die. On its own the bend line will be in the weakest portion. So you make the cut so the bend line is the weakest portion. Bending parts with missing material near the bend line is one of the few areas where an apron brake will outperform a press brake.
 
so let me get this straight, you weld with the plasma cutter? (i never used one.)
No, you cut dotted lines where you want to bend the material. Usually more than 50% of the bend line. Then, you bend along the line of cuts, which offers much less resistance, because you are only bending a fraction of the amount of steel.
THEN, after its bent, you can go back and fill in the slots with a weld bead, and sand it smooth.

The advantage to this technique is if you dont have a brake of sufficient capacity or length, you can do it on lighter stuff without a brake, as there is much less resistance to bending.
 
+1 on ries, I stuffed 3/8” in my 4’ edwards folder and bent it after gashing, I had to open the blade right up though, not sharp but bent!
Mark
 
so let me get this straight, you weld with the plasma cutter? (i never used one.)

Sorry for the confusion. The perimeter of the part is cut with the plasma cutting machine.At the same time ,slots are cut wherever the part needs to be bent. There are no loose pieces.Next the part is easily bent by hand. If the box needs to be strong,you can weld the corners ,using what ever welder you have. Edwin Dirnbeck
 
As a machinist you remove metal to make something. But sheet metal is so very different. You need to think beyond what you know to design parts and products with sheet metal. Just a few bends add so much strength to a floppy piece of sheet metal. When you can cut it with a laser there are so many options to think about.
I have known about that type of bending but have not used it yet. I do have a Trumpf press brake, but only tooling up to 10 gauge. Laser can cut 3/8. So??
 
Another interesting thread Ed. I've been around all kinds of metalworking but have never seen that technique before. Our tinsmiths had press brakes that were pretty hefty so they probably didn't need to slot it like that.

Thanks for posting it.
 
I did this on a small run of gym equipment I was building. The charge to have them press broke was a lot high so a slot it was. Worked great on some 1/4” material.


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I was expecting some type of carbon arc setup to heat the metal before bending. I think it was the Buick wildcat that had a folded rear window like a boat tail. It had a embedded heating wire inside the fold/bend. I think it was used as an antenna after cooling.
Bill D
 








 
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