sheet metal bending
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Posted by: lar ®

02/04/2007, 11:02:47

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we have been bending sheet metal on brake machines
we will be building a rollforming machine to bend the sheet metal in steps
could you provide formulas to calculate forces needed to bend sheet metal
for example, how much force has been required to bend the sheet metal of .062 thickness, 50,000 psi 10' lengths with a 2" flange on the brake
the majority of our material is .062 max thickness and 50,000 psi max
the first bend will be 18 degrees of two sides with a 2" flange and a 6 " web with five steps until we obtain a 90 degree bend, most material will be 10' lengths running the rollformer
thank you
lar







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Re: sheet metal bending
Re: sheet metal bending -- lar Post Reply Top of thread Forum
Posted by: randykimball ®
Barney
02/04/2007, 23:43:47

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There are many things to consider in rollforming. When you form a large flange as in 2" you must consider the distance between the stations. It takes more distance between stations as the size of the flange goes up. This is because you are stretching the material as the flange is being formed. To prove this to yourself take a piece of paper and pretend it is in a roll former. Bend one corner of one end up and crease it as if you are in a stage of the rollformer to make your flange. You can simulate by only bending a 1" flange. This will in effect simulate twice as long (so an 11 inch paper simulates 22 inches between stations of a 2" flange). You will notice that the edge does not stand up verticle to the 11 inch axis. If you force it you will tear the paper. Now go ahead and crease at 2". Now you have a vivid picture of the problem. Now you see that distance between stations is vital with larger flanges or you will cause the edges to flutter or develope a "click". For .062 thickness (16 gauge) I would use 2" diameter shafts, gear driven stations, driven upper and lower stations, and idle (free spinning) later flange rolls. (I curently make my living with roll formers)




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Modified by randykimball at Sun, Feb 04, 2007, 23:48:53


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Re: Re: sheet metal bending
Re: Re: sheet metal bending -- randykimball Post Reply Top of thread Forum
Posted by: kwandrey ®

07/28/2007, 14:41:42

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Greetings my first post. and my first rollformer in progress.
well I missed the formula on station spacing and am running into problems. .020 aluminum (soft low temper flashing) 2-9/6 and 15/16 legs on the profilebasically a U shape 3" flat horizontal then 15/16 leg vertical then the 2-9/16 folded back over the top horizontal. I currently have a 12 station dual sided configuration at 6" station spacing based on 3" nom rolls all rollers are chain driven. If I combine 2 bends does that help the spacing formua? I'm hitting this metal pretty hard 45 90 hits my stations all work althought the material does exactly like you mentioned buckles etc actuallt stalls in the machine. Planning on trying to re-tool and start 2 bends at a time then form them together. my first attempt is each station does a single bend last stations use small bearing rollers on top to get inside the U shape. I tooled a rollformer for this customer and had good results 5 years ago for muck simpler part short bend legs and hes still running it so maybe got over confident on my abilities at this.
Ken autotech@nc.rr.com







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