Roll Bender Advice

Hello,

I'm very new to metalworking and I need some advice on a roll bender to produce a specific part. I'm looking to find a used roll bender that can handle 3" wide flat bar (.19" thickness of 1045 steel). The primary part I will be producing with it is 30" long and I need to accomplish a diameter of 26". I will need to produce around 100 of these parts per week. I've looked at some Baileigh benders (R-M10 and R-M40) as potential machines. I could use help on selecting the most cost effective solution for my application. Any help is appreciated, and please let me know if additional information is needed.

Thank you,


Michael

From your description it seems like you want to produce a part of a circle at 13" radius and a circumferential length of 30" out of 3" x 3/16" strip.
Is that correct?
If it is,the best tool would be a set of initial pinch rolls,although this would leave a short flat at each end.If you can`t have a flat,you would need to preform the ends by pressing before rolling.

Edit:Thought I`d better explain what I meant by flat.The flat bit at each end would be about 1.5 to 2 times the material thickness.

I don't know about the models you mention, but I bought Baileigh's smallest, the RM-3 planetary roller, a while ago. Before ordering I spoke to them and they assured me their roller was superior to the similar but half priced Harbor Freight unit. The one they sent me was as sloppy and loose as the HF junk, but heavier built. I returned it and they sent me a hand selected one, that was certainly better, but just not what I had hoped for. Still too much play, and rolling spirals instead of coils in brass. Sigh....

Maybe their larger rollers are better, probably the european made ones are, but the chinese stuff is disappointing.

I've made my own, can't recommend that either - takes WAY longer than expected, but very accurate and nice.

Michael,

I looked at the benders you mentioned. The more cost effective one seems to be manually operated...'armstrong', if you will. At your target figure of 100 rolls a week I would surmise you would be in physical rehab at the end of the first month.

I wouldn't even consider a roll unless it were powered. Rolling 3/16" X 3" is not going to be a cake walk by any means unless the machine is powered.

The Baleigh rolls you note will leave a pretty long flat on both ends of the bar. The ring will have to be tack welded and run through a few more time to make your perfect 'hoop'. That's my take on the deal.

Stuart

Stuart's advice is bang on. I roll brass, still within my physical ability, and I welcome the workout.

It's another $1800 to get from the manual to the powered rolls. Seems like it would be much cheaper motorize it yourself, if the capacity of the manual machine is adequate for you.

I built my own roller for about $2000. It was a lot of work and a good learning experience as it had some of the first parts out of my CNC mill in it. I powered it with a hydraulic motor running a planetary gearbox I had laying around. I designed it to take standard dies so in a pinch I could buy dies off the shelf. I've always made my own though from 4140HTSR. It does leave a long straight bit at the end of the bars that you run through so you have to be willing to discard 8" or so off each end if your just doing arcs. I built it for a specific job for a very good customer but by the time I got it finished they changed their design to not use rolled parts
Jordy

Shop outfitters makes a nice manual bender, i think it only goes to 2 inches wide. Mine is a copy of a Chinese copy of the shop outfitters one. The Chinese ebay photos were easer to reverse engineer from. Kind off funny copying a Chinese copy, off course no child labor was used in the making of mine. My bender is three inches wide and started off manual, that was no fun so i added a winch motor from which i removed the drum and added a sprocket.

Sorry about the crap photos, uploaded from my phone with taptalk, seems to make the resolution suck

As others have mentioned, a 3 roll bender will leave a flat at each end.
So if you NEED 30" of even curve, you will need to bend about 48" or more, then cut off the flats, if you are just running blanks thru a three roll machine.

there are a couple of alternatives to this-

First, with a good enough 3 roll machine, you can prebend the ends a bit- I have a neighbor who has been running a Roundo for 30 years or so, and he can do this in his sleep- the Roundos have hydraulic powered up/down on the lower rolls, so you can prebend. But a new Roundo is well north of twenty grand.
http://www.roundo.se/pics/1/35/R-1 through R-21-S_Eng.pdf

Second, you could make dedicated dies, and do this in a hydraulic press- 30" may be within the range of a Hebo, which is a german ornamental iron system- they make a bulldozer style horizontal press that is used to make shaped pickets for fences and railings that could knock out 100 of these in an hour or two. Again, not cheap- though cheaper than the Roundo, I would guess.
The WTZ24 horizontal is the one I am thinking of- USA Hebo
here is the data sheet, showing a bunch of different complex shapes, being pressed, all much more complicated than a mere curve. The dies are pretty simple, just big chunks of flat plate. Of course, calculating the springback is the hard part...
http://maschinen.haboe.de/fileadmin...inen/Hydraulikanlage_WZT24/WZT24 Werkzeug.pdf

Third, just buy a hossfeld- $800 or so, plus a set of angle iron, flange out, dies- definitely under two grand, total. Bolt it down, put in the 13" radius dies, and hire a college kid who works out, and pull em by hand. It will probably take about 2 minutes per part, in multiple pulls, to pull the 3" against the fixed radius dies, and they come out pretty darn good, considering there are no motors, switches, computers, hydraulics, or electricity involved.
Bar and Angle Iron Bending Tooling Attachments | Tube Fabrication and Metal Fabrication Equipment by Hossfeld Bender
you would use the setup in number 10- angle iron, flange out. This will bend the bar to the end, no waste, no cutting.

I have owned a hossfeld since 1978, hand pulled literally thousands of circles and arcs on it. Its bulletproof, low tech, and it works. But its nowhere near as "modern" as paying twenty or thirty grand to push a button.

In the sheet metal shop I worked at we had a set of powered rolls with 4 inch dia , 48 wide rolls, the "flat" part was shaped with a mallet before and after rolling ---- it can be done quickly and comes out nice--- you didn't mention what the end product was ?

You would have to be built like Lou Ferrigno, and take as many steroids and HGH as he did, to shape 3/16" 1045 with a mallet. That stuff dont wanna move quite as easy as 20 gage will...

I am old.
I like mechanical advantage, brute force is for young people who havent figured out yet they are gonna break eventually.

suggestions

Wow - I'm new to this site and the amount of knowledge and support from everyone is incredible. I really appreciate the insight. I've tried to digest most of the suggestions and here's what I'm thinking:

- I'm sorry I forgot to mention in my original post that the starting piece of flat bar I am working with is cut with a contour. So, from plan view it looks like an arc to begin with and I need to bend it on the other axis to a 13" radius (see attachments). When I was thinking about using a 3 roll bender I am assuming that the original shape of the flat bar doesn't cause any limitations. As some have suggested using presses and smaller manual benders it looks like this may cause some limitations.

- I do not have the option to trim the ends, although one end is designed to have a 4.5" flat in the end. I've tried to attach pictures of before/after bend for reference.




- I don't have the budget for a Roundo machine that has adjustability on the lower rolls which allows for prebending. Are there any other cost-effective alternatives to a Roundo machine that allow the same functionality?

Again, thanks for everyone's help.

That is not an easy part to make- I hope you are getting decent money for those.

A three roll bender will read this not as a 3" wide part, but as a 14" wide part. Trying to run this part thru the Baleigh's you indicated will simply not work. It will want to unbend your precut contour- which is perfectly possible.
You will end up with nothing like what you want.

Theoretically, an incredibly skilled, or lucky, operator, could do this with a set of 3' wide sheet rolls. But you would probably have a pretty high reject rate- it would require feeding the part in diagonally. And the sheet rolls will bend different parts of it to slightly different radii, depending on the width of the material in the roll at any given point.

If this part needs to be precise, and every one exactly the same, the only way I can see doing it is making 3 D dies for a large hydraulic press. Since the material is only 3/16", You might be able to get away with built up MDO dies, although I wouldnt expect a really long lifespan for them, but at least you could proof the concept.

I think you are in over your head, if you really need this part as exact as the metric drawings require- assuming its aerospace or something.
To reliably make this part in large quantity, I am guessing the tooling and machinery is going to be a lot more than a used taiwan roll bender that only cost $1700 new.

Who designed this thing, anyway? How much did they expect it would cost? And have they ever designed anything that was actually manufactured out of metal before?

If I was making ONE of these, I would imagine a couple hundred bucks apiece. Just for nusiance value. I could hand bend these on a hossfeld, but every one would require bending, checking, tweaking, checking, and rebending. Slow, and requires someone who is patient and skilled. You cant afford me- just ask my wife.
If I was making hundreds a week, I would absolutely go with dedicated dies in a 4 post hydraulic press. Not cheap. Amortized over a few tens of thousands of parts, do-able, assuming the part price was reasonable. But this is not, no how no way, a ten dollar part. Not unless you need a hundred thousand a year or more.

I have seen parts similar to that made in quantities of probably hundreds a year, the parts were bent on purpose made bending machines which slightly over bent and then finished by beating with a mallet over complex wooden formers.

As others have said this is not a straightfoward part , I am not sure but I wonder if the developed shape could be cut out and then relatively simple rolls used to produce the final shape, this would obviously be very expensive in material though.

Edit I see now that you are doing exactly what I said above.

your drawing appears to be a segment of a cone? if so then i would have the part cut by plasma or laser and then roll on a pyramid rolls.very easy to do.you would not need a large rolls.

najnielkp said:

your drawing appears to be a segment of a cone? if so then i would have the part cut by plasma or laser and then roll on a pyramid rolls.very easy to do.you would not need a large rolls.

Click to expand...

I am dubious.
I own a 4' wide set of pyramid rolls, and I have done this. In fact, I have done several projects involving dozens of parts rolled like this. It required a fair amount of custom tweaking of each piece, and, even then, we were welding them, and had to clamp and pull each one into place. And that was 1/8" aluminum, not 3/16" 1045.

It is not a very repeatable process. It is entirely up to the operator to judge the exact angle you feed the part at- I dont see how you could use any sort of jig or stops to do this- maybe sharpie marks, but thats about it.
Then, as i mentioned, it bends different parts of this curved workpiece different radiuses, depending on the resistance it is finding- so the tip of the first corner in will be tighter than the widest part towards the end.
Then, you would need to stop the machine, and roll the part back out again, at precisely the same point every time, to get that flat on the end.

If tolerances are loose, and variability in radius and location of the curve is Ok, then, yeah, this could work.
But the drawings are in tenths of a millimeter, and tenths of a degree.
This would indicate to me a degree of precision far beyond the "just kinda sorta" that you get using pyramid rolls and feeding in at an angle.

If its just overzealous draftsmen/engineers with too many decimals on their CAD program, and the final assembly will pull the part into place, and a quarter inch or more of range is acceptable, then, yes, a pyramid roll would work.
How big "not large" would be is somewhat subjective, however. I have a set of 4' wide, 4 1/2" diameter rolls, about 5hp, and they will not do this- they wont physically open enough to do 3/16" reliably. And that is about a ten thousand dollar set of rolls, and at that price, you are talking Turkish imports. To do 100 a week, reliably, I would want a bigger set- one capable of 4' x 1/4" would be my choice. Again, even used, far more expensive than the little hand crank Baleigh.

If I was to bend these, I would bend them hot, from a furnace, into a jig, putting the straight part into a holder of sorts and pulling/bending the flat around the jig in one go/one heat, they are only 3"wide and 3/16 thick, I reckon it would work. But as others have said I would charge these so as the customer bled from the arse when he got the invoice. The work involved to build the jig is complicated, then you need a furnace to be able to heat say 10 at a time of these strips all over to about 1100 degrees C, then you will need to tweak the process so as the flat bends nice and uniform, as you bend it on the side it is probably going to want to twist off the jig. That is how I would approach this job, hot, in one go, in a jig.

"Who designed this thing, anyway? How much did they expect it would cost? And have they ever designed anything that was actually manufactured out of metal before?"

Pretty much what I say every time I quote a new job....

Section of a cylinder with a poorley defined flat.

Could be described as a helix.

Plasma cut from a section of pipe and then the end flattened?

A precut blank would not be a contour but a flatbar with an angle cut on each end.

Mabey they could be rolled 2 at a time from flat bar and the flat is from the as rolled condition?(and is acceptable)

najnielkp said:

your drawing appears to be a segment of a cone? if so then i would have the part cut by plasma or laser and then roll on a pyramid rolls.very easy to do.you would not need a large rolls.

Click to expand...

Ries is right on the money...you can tell this guy works with alot of metal.

I could do this job with our plate roller and a cnc mill. The plate roller is for the general curve/helix, the cnc mill is to hit the ridiculous dimensions after the plate roller has "massaged" the strap/plate/bar into rough shape.

If the data on those drawings are correct, these are parts for some kind of "egg-beater" windmill or some weird-ass hydro turbine. Charge accordingly.