Thread: How much muscle needed bending 2.1 m of 3mm steel on panbrake

Wow you had better be a big boy.
What sort of radius do you have in mind?
I've not seen anything homemade that would come close to folding that thickness at that length.

I've folded that sort of size but it was on a 60ton press.
If I'm reading the first table I googled correctly your looking at something in the range of 15 to 38 ton per meter(depending on radius)

Stuart

Tried this once when I younger and stupider. Not only will you need to be built like the incredible hulk but the clamping pressure will need to be huge to prevent the material moving as you bring up the fold 'leaf'.

I am watching the equipment market (with frustration due to lack of funds at this point in time) of how cheap pressbrakes are due to the economic downturn.... perhaps a better option?

I have used a beefy commercially built hydraulic panbrake to fold 3.0mm MS at 1800.0mm long.... inside fold radius was around 6-7mm from memory.

Thanks very much lads.

Bend radius is as sharp as I can get it, I basically need it folding at 90 degrees.

Guess I'll have to make a very short version just to give me an idea of what forces are involved. If I make a mini folder that can bend say 200mm long then I've got to multiply that force by just over 10 for my longest length.

I'd rather find out the worst now rather than after I've attempted the build.

I was wondering if I'd have to go silly with the construction. I've got some big chunks of steel I collected some years ago, maybe I can put them to use. They'd cost hundreds of dollars if I had to buy them. I'm very cash strapped at the moment too, got my own little excavation business and things are dead. Who says we aren't in a recession.

Cheers,

Keith.

Hi,
go here

Sheet Metal Calculators

for the calcs,
Based upon 3mm at 1800mm

Which for the table is .125 x 72" and for a female die opening of 3/4' ON 135 DEGREE FEMALE DIE
angle it gave 48 plus tons.
Its the length that drives the bending forces up bigtime!

Grahame

Originally Posted by beefy

I looking into building a manual panbrake to put right angle bends in 3mm steel sheet. The longest fold I should ever do would be about 2100mm. Anyone got any idea how much muscle power is needed to bend 3mm at that length. Would I need to hook up some hydraulic "assistance".

Also does anyone recommend any particular plans for a sturdy unit like this. Lots of the homemade units I've seen don't go this long, or they are bending pretty thin sheet.

Cheers,

Keith

Sorry to say, two words. Forget it.
3mm over 2.1m - that is a hell of a lot of pressure. Try to find a manual panbrake from a commercial manufacturer that can handle that, (I doubt you will) and take a good look at the general construction of the unit. That thickness and bend length is really hydraulic territory.

Hi beefy

Do you have a lot of bends to do and want to keep job in house? If not it may be better to just take the bending requirements to a fabricator with a pan brake or folder. I don't think it would cost much per bend

Just as interest and not what you are asking
https://www.woodworkforums.com/f65/ma...2/index10.html

Good luck.

Cheers.

Originally Posted by Grahame Collins

Its the length that drives the bending forces up bigtime!

Well not exactly, the bend force goes up with length. Its the radius that will knocks you around, it can more than double the force required for a given bend. Still 10 times the length it going to be something like 125 times the deflection isnt it?


Just to give you an idea what you are looking at beefy


The biggest manual machine H&F have on their site and its not big enough.
https://www.machineryhouse.com.au/S264
(infact I'd like to see someONE fold 2440X2mm on it. Never folded anything so thick at that length on a manual machine but I have on 4ft machines.)

You'd need something more like this. It might just get 3mm over 2100mm. https://www.machineryhouse.com.au/S583B
but it might not, you might need the next size up.
https://www.machineryhouse.com.au/S584A

Small, cheap and light..... its not going to be any of those.

Depending on what your plans are, farming it out as log said or welding in the corners could be the go(though that would be a lot of welding).

Stuart

Thanks again everyone, turns out it was definitely a question worth asking.

I basically looking into doing some business making those weathering steel light boxes (flat panels too which don't need bending, but the light boxes are really wow when it's dark). A standard sheet of steel is 2440 by 1220 so I'd need a say a 100mm depth and say another 30mm lip behind to give the edge of the sides some stiffness. No, hold on, the lip at the back would be the mounting point so it would need to be much bigger to give some "beam strength". I'll go with 100mm for now. Guess that takes the max bending length to 2440 - (100 + 100 + 100 + 30) = 2110mm.

I've got my homemade cnc plasma table running fairly good, and now I've got to a stage with the arty software to produce cut paths from images & line drawings, create geometric patterns, etc. Now I've just got to start making some of my own patterns and drawings. I've done a bit of cutting from my mechanical cad software files but the arty side of things can get a bit difficult when it comes to producing a cut path. Think I've cracked it though and here's a picture of my first real arty cut. The sheet of 3mm mild steel I had was going rusty so thought I'd use it as a test subject. The blue behind it is a bed sheet on the ground.

I'll call around to get prices from 3rd parties to do the folding. Hopefully I can still keep the selling price down enough to make sales.

Cheers,

Keith.

20130112_113338 - modified.jpg

As a matter of interest, 3mm steel also comes in 1800X1200 as a standard size. Even so manual bending of 3mm steel is going to be grunty at the very least.
If I am hearing you correctly, you plan on making decorative panels, with a cnc plasma cut design. I would add a caution that there is a possibility of distortion occurring on the large flat surfaces leading to a rippling or drumming effect when hung.
Plasma is a good process and your cnc setup will add to its capabilities for sure, but for this type of work laser cutting would be the ultimate, not to say that plasma won't work. Watch the duty cycle of your plasma too, any automated process really tests a duty cycle.
I don't know what services you have near you, but my immediate thought would be to farm the folding out to someone with a brake press. You will get far better results at a cheaper rate than to try to build this yourself. Even commercial workshops farm some work out. At my past employer, we had a 60T hydraulic brake press which was used for probably 85% of our folding, but the old girl had its share of use and abuse, so for the fine work we would access a cnc brake press nearby, because it would cost us more to play around fooling our press to fold accurately than it cost to use their press and the potential for failure was removed. One crease or hammer mark can destroy several hours and hundreds of dollars worth of work.
If I could offer one final word of advice, it would be to start small and concentrate on smaller items as you will have less money tied up and can also use thinner material - say 1.6mm or even 1.2 - this will fold comfortably on a manual folder and will still cut well with a plasma, (still seriously consider farming out the folding, it will take a long time to recoup the cost of a folder versus paying for folding). Starting this way will allow you to refine your setup and gain knowledge to tackle larger pieces, secondly the consumer can be extremely fickle in their tastes and reject an item that you think will sell like hot cakes, rendering it little more than expensive scrap.

Karl,

you're a valueable guy on this forum, thanks again for your input.

Know what you mean about distortion, it's my enemy whenever heat & metal come together and I want everything to stay exactly the same. I was welding some 90mm tube onto 16mm mild steel (fillet joint around the pipe end) and the 16mm steel actually bent up with the contraction force of just one weld, couldn't beleive it.

My cam software has an option called "reduce distortion". Basically you set the minimum distance between cuts so instead of it doing the quickest route to the next cut, it goes far away to the next one. The cut takes a bit longer but the heat doesn't build up in one area. Helps quite a bit. Use Hypertherms "Finecut" tips for the panelling to reduce heat input to a miniumum.

I'm OK with the duty cycle on my machine (Hypertherm 1250). It was a fairly warm day when I cut those panels and the internal fan kicked in but stopped again so it was handle this cut fine.

Well everything has got much more simplified now. It's basically a matter of see what it will cost me per panel to have a 3rd party do the folding. That leaves me to concentrate on producing my own patterns, maybe it will be a blessing in disguise.

My main thought now is will they want the flat steel sheet without the pattern already cut. If they do then that makes things a bit more awkward. I'll have to make a grid type support that goes inside the box and put that on the cutting table. But what's life without some adversity.

I'd love a laser Karl but I've skimped and scraped for years to DIY build this table. All spending and little profiting at present LOL.

Cheers,

Keith.

Originally Posted by beefy

My main thought now is will they want the flat steel sheet without the pattern already cut.

I dont see why they would care unless you were removing so much material as to make handing difficult.
Other than that is depends what radius you spec, what sort of folder they use and how close to the edge you want a cut to be. If you want the cut closer than 10mm I'd say you will be cutting after folding. 10-20mm depends on folder and radius. 20mm or more cutting before folding should be fine.

Stuart

Beefy,

For your light boxes behind your cut panels, surely 1.6mm ms would be sufficient. If you use LED's as the light source, the light boxes won't have to be waterproof. Therefore you could stitch-cut the fold lines. Cut 25mm, leave 3mm, cut 25mm, leave 3mm etc etc.

I used this technique when designing light fittings. The folds can then be done almost by hand.

Hope this helps and good luck with your new venture.

Ken

Thanks lads,

unless a customer specifically requested otherwise, I can keep the pattern at any distance I choose from the edge so that's within my control. I'll ask the folding guys about that one.

The stitch cutting never crossed my mind, I'm going to do a little test one to see how that looks after it's bent. That could be something I use for various things in the future. My cam software has a function to leave tabs and I think I can control the tab width and the distance between them. The only issue is there's a new pierce for every cut which blows out a little hole. Normally the cut "leads in" to the cut line after starting the pierce a short distance from the cut line. Maybe I could alter the programming to start piercing after movement has started and see if that works.

Been doing a few calculations to see what the basic costs are before any profit is added on. It gets up there pretty quickly once you've added in weathering steel, opaque plastic liner, lighting, bending costs, cnc cutting costs, labour, etc. Think I'd better see what the going prices are on these gizmos before I look at trying to do it cheaper.

General panels are easy, chuck a peice of steel on the table and cut it out, then maybe make a frame to mount it on. I'm quickly finding out the journey's a lot different with a light box though. It's also come to my attention that I'd have to cut the corners out quite precisely so that when the flat sheet is folded the corners come together perfectly. That also adds an element of risk into the equation, maybe I just like getting into deep water LOL. Suppose the folding lads should be able to give me precise dimensions for the corner cut outs. The table is pretty accurate so should do that within their specs.

Cheers,

Keith.

Beefy, if I have to laser cut a box, for example, with 4 sides turned up, I laser cut a hole in the 4 corners. This ensures that the folded up sides meet neatly.

The dia of the hole=sheet thickness.

Attached is a typical dwg, zoom up on an internal corner to see what I'm talking about.

This part has stitch cut folds.

Ken