Narrow width roll former

Thomas Green · Oct 5, 2007

I have a special need to roll some flat stock into a flat ring. The material is 4130 steel sheet (normalized) and it pretty darn tough. The flat form is .063" (1/16) thick by about 1 1/2" wide by about 11" long and when rolled it needs to be about 3 1/2" in diameter.
Perfection of the final rolled component is not needed.

My problem is finding something like a slip roll but one that is HEAVY duty with the narrow, tough capacity to perform this task in a commercial environment. I anticipate needing to roll about 3000 per year.

The slip roll I tried is simply too flimsy and of course way wider than necessary (36"). Also the 4130 wears into the rolls pretty fast...

Do any of you know a tough tool that will do this? Is there somehow to use a lathe for this? I have a darn big Mazak lathe but can't see a safe and reliable way to use it for this forming job. Thanks, Tom

Ries · Oct 5, 2007

A slip roll is for sheet metal.
To roll a ring, in 1 1/2" wide material, you need a ring roller, not a slip roller.

3 roll ring rolls should do this.
You might need to pay extra for hardened rolls, if your material is really that tough, but I kinda doubt it- I roll stainless in mine all the time, and while there is wear, its not excessive.

Talk to these guys- they sell very high quality Italian made tools, and talk with a southern accent- I have had one of their machines for 5 years or so now, and subjected to all kinds of things the designers never imagined, and it has held up very well.
http://www.eaglebendingmachines.com/

toolmakerjim · Oct 5, 2007

hey yall whuts rong wid a soutern akcent...jim

Peter from Holland · Oct 6, 2007

It can be made on a hydraulich press
Make a die with a halfround gap and a piece of round stock First press both ends in shape Then place a bridgeconstruction on top of the round stock for the final bend to allow the flat stock to complete the 360 dgr
Peter

metlmunchr · Oct 6, 2007

To roll 16ga material that tight you might need to use a combination of Peter's method and a ring roller in order to end up with uniformly rolled parts. Its pretty simple to make a press forming die set where the upper die is a piece of round stock and the lower die is a segment of a circle. This would be used to pre-form the radius on the ends of the stock pieces so they don't have straight lengths at the joint.

If you don't have a need for generalized ring rolling capability, it might be far cheaper to build a dedicated wiper type rolling fixture for the parts. It would basically consist of a base with a round spud of the proper diameter, a piece to rotate around the spud, which would carry the wiper roll and have a handle for operation, and a cam locking device to hold the material stationary. For rings that narrow, everything could be cantilevered so the finished ring could be lifted off the spud without any disassembly. Pre-forming the ends would still be necessary, but the entire process should be well under 1 minute per part for near perfect rings.

Peter from Holland · Oct 6, 2007

metlmunchr
Having made the press forming die why not go the whole way and finish it on the press It will take just pressing 4 times I estimate to make perfect round rings It just needs a special U or box shaped upper die so it is free for the ring to close
Peter

L Vanice · Oct 6, 2007

I have the instructions for using the Di-Acro bender. It shows exactly how to do this kind of work with very simple tooling. There are usually some No. 2 or 3 Di-Acro benders on eBay.

Larry

metlmunchr · Oct 6, 2007

Peter,
I've done that in the past. You have to build an upper die that's supported from the ends by legs extending down from a baseplate. The upper die itself can be a section of round stock, but there has to be daylight above it for the ring to close. The upper die has to be secured by a removable shaft such that the finished ring and die can be removed from the frame in order to slide the formed part off the die. I was forming parts in a press brake, so the alignment of the upper and lower dies was taken care of by the machine itself. I'm assuming he doesn't have a press brake but might have (or could justify) a hydraulic shop press. Forming complete rings in a shop press would require the die assembly to be self guided, so it would get sorta complicated and the end result would still be a rather slow process. If I was doing the job myself, and making 50 or so parts, then I might do it in the press brake, but for 3000 pcs I'd want something a lot faster.

Larry,
What I described above is sort of a single purpose DiAcro. If the real McCoy is available at a reasonable price, that would be the way to go instead of building something.

gmatov · Oct 6, 2007

Tom,

I was going to suggest this when you said you wanted to try it: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=36790

70 bucks, cheap enough to see if you want to spend for a better one, but it says 3/16 X 1 stock, so dont know, but it looks like the rolls are flat, no shoulders, would maybe handle 1 1/2 wide.

If you are going to feed with 11 inch pieces, you are going to have to form about 2 inches on each end to a curve to complete it. Either that or you use 15 inch pieces and cut to close the circle.

OR, you feed the max length you can buy, mebbe 21 foor, at a bias, wind a long close spiral, cut to length for a 3 1/2 inch circle and press to straighten and weld, if called for. Less scrap and no need for second op.

For 70 bucks, you can see if the principle works, if it does, go buy a 600 buck machine that might stand up a bit better, or more if motorized.

I know HF is anathema, but you ARE trying to develop a system.Develop on the cheap, improve with money after you prove it.

Cheers,

George

L Vanice · Oct 7, 2007

scan of Di-Acro circle bending instructions

The instructions say you need a Bender No. 3 or 4 to do parts 1.5" wide.

Larry

Ries · Oct 7, 2007

Theoretically, I guess you are right that a heavy enough slip roll would do it- But its pretty rare to find a heavy duty one that doesnt have rolls too big to make a circle that big.

Me, I am always looking for excuses to buy another tool- and tools that I can have a paid employee run without too much thinking involved. Or fussing, which generally costs a lot more per hour.

So If I had to do 3000 of em, I would probably go for a small motorised 3 roll roller, as its pretty much a no brainer once the rolls are set for the right radius.

Certainly you can roll circles like this with a hossfeld or diacro bender too- I have rolled thousands of circles by hand with my hossfeld, and the advantage to that is you would use a fixed radius die, so every circle would be the same radius with no adjustment of radius.

But for production, I prefer a machine, that you turn on, feed the material, and get a finished part out the other end- easy to pay somebody 12 bucks an hour to make a hundred at a time.

I suppose if you already have a press brake, and have experience building the tooling, it would be a good solution- but to buy the entire setup from scratch, a new press brake would cost 4 to 10 times what a dedicated ring roll would. Used, depends on where you live, and how much you want to fix.

These guys actually sell automated rolls that do this- but I would guess you would need to be doing 3000 a week to justify the cost-
http://www.coletuve.com/automatic_high_speed_plate_rolls.html

metlmunchr · Oct 7, 2007

A slip roll would work fine once the ends are preformed. Something like the DiAcro 12" wide slip rolls would probably be more economical than bigger rolls, and their stated capacity is 12" of 16ga, so they should have plenty of capacity.

The Tennsmith roll with 3" dia rolls is about $3600 including the stand, and a decent one would probably bring $2500 in the used market, since light sheet metal equipment never seems to go cheap. Cranking the DiAcro thru 3000 parts would definitely be a lot less work than doing the same parts on larger manual rolls.

I doubt any of the cheap, light weight imported rolls with ratings of 22 or 24ga would work satisfactorily since the ones I've seen have sorta sloppy overall construction. OTOH, an old set of 3ft 22ga Pexto rolls would do the job very well.

metlmunchr · Oct 7, 2007

Ries,
Question about rolling with a ring roller. Would the ends need to be pre-formed to avoid straight sections at the joint, or will the ring roll take care of that?

Actually, the only time its worthwhile to form something like this totally in a press brake is when the wall is heavy and the diameter is small. When I used the brake, I was forming 3/16 x 3 stainless flat bar into circles with an ID slightly over 2". For that it was worthwhile, but on thinner stuff its doubtful the press brake would be a competitive solution.

On that particular job I could've taken 2" sch40 SS pipe and knocked .030 out of the bore for half what I charged them to form the flat bar. Would've been the same part they'd drawn, but with no welding required. They were doing the welding. They weren't interested. I guess its easier to pay twice the money for 200 blanks and do 50ft of TIG than to change the drawing. Doesn't bother me though, cause I take a real liking to people with more money than sense

Joe D Grinder · Oct 7, 2007

Made my ring roller over 20 years ago. Only one roll powered. used a hard facing rod in my welder to "spritz" some very small spatter onto the powered roll and that keeps the roll from slipping on the workpiece. It also very slightly textures the material, which in my case hurts nothing. I regularly do 3"x1/8" material with it. You may want to seperate the material you will be bending, since each 20' strip may be slightly different temper and require a different setting on the ring roller to complete the circle. I finish the flat spot on the end with a hammer and wooden block.....Joe

Peter from Holland · Oct 7, 2007

metlmunchr

My idea was to have a upper die with one side open
Just a single heavy leg on one side and a horizontal leg
With the 15 tons tops requiered for bending this I think it is possible And then a electric hydraulic press
Peter

Ries · Oct 7, 2007

The machine Doug linked to is the real production way to go.

My standard 3 roll section roll, the ones used to roll angle iron, or pipe, or big square or round bar, do indeed leave a flat end at both ends.

But when I gave the Eagle bending machine link, I was thinking about machines like this-
http://www.carellcorp.com/hightech2roll.html

Its similar to the one Doug posted, designed to make cylinders with no flat spots.

I often roll spiraled coils, from full 20 footers, then cut them into rings afterwards. But I wouldnt do this with 16 gage sheet.

If I had to do a few, I would use my hossfeld- quick, relatively cheap- brand new, with dies to do this, around $1000- and a flexible tool that has hundreds of other uses. Diemaking is a lot simpler than it would be for a pressbrake- you can make circles like this using a piece of pipe or round bar for the die- I have pipe cutoffs, 3" long or so, in sizes ranging from 3/4" up to 12" that are all just scrap.
The hossfeld just wraps it around the die. You size a bit smaller to account for springback, but once you have the die, it is quick.

Thomas Green · Oct 8, 2007

Well, as usual I got a "ton" of information by just asking!! What a great forum, I can't thank you all enough.

I think I will initially try building an upper die with round stock for our Cincinnati press brake... I kind of like the "three hit" idea to end up pretty much without flats...

My press brake guys are pretty good with making tooling. I will suggest using the 90 durometer poly urethane for the lower die... we use it for other products so we have pretty much got it "half" done.

I am going to look at some of the suggested "ring" rollers but at least for now I have a simple direction to try first...

thanks again, Tom

Thanks again, when I have

deere_x475guy · Oct 8, 2007

Thomas check this thread for one I built.
http://www.practicalmachinist.com/cgi-bin/ubbcgi/ultimatebb.cgi/topic/1/24931.html?

Thomas Green · Oct 9, 2007

That is exactly what we will end up with one way or another... the guys on the press brake can make them for now but the welder wants to do his own... so I am leaning toward initially ordering the "harbor freight" one and then modifying it to see how long it lasts.... will report when I have data.. Thanks again, Tom

Rick Hand · Oct 10, 2007

A friend of mine has been planning to build a ring roller using an old horizontal mill for the powered roller and two non-powered rollers bolted to the table. The ends would probably still need to be formed.

Rick

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