Bending Square aluminium tubing
 

I need to bend 1.5" x 1.5" tubing with a .063 wall to a radius. It will be a four sided frame. The top being 14' straight the two sides 36" straight with a lower radius connecting to make the frame. How do I bend the lower radius

Re: Bending Square aluminium tubing
 

help

Re: Bending Square aluminium tubing
 

I've never seen a team bend square tubing. What most teams do is one of the following. You could weld it but I'm guessing you don't want to do that right now. Or you could rivet them together using a gusset plate or use bolts if you want to. If you want strength and don't plan on making changes too often, I would suggest using rivets

Re: Bending Square aluminium tubing
 

For low-strength applications you could cut notches out of one side with a band saw (or whatever) and then bend it. We did that with some aluminum angle for the back support of our ball shooter back in 2006 and it worked pretty well. I wouldn't use this method for anything that's going to be under a lot of load without reinforcing it though.

Re: Bending Square aluminium tubing
 

I think he knows what everyone normally does (riveting and welding) but bending tubing like that can really be stupid simple with not that much hardware. You could use a machine but that is very expensive and probably not what you are looking for. The method I think is most appropriate is what this gentlemen did https://www.youtube.com/watch?v=vguWbHxzG98 . This is just a bigger verson of this http://www.lowes.com/pd_472951-295-MCB1-2_4294653949__?productId=50114251&Ns=p_product_qty _sales_dollar|1&pl=1&currentURL=%3FNs%3Dp_product_ qty_sales_dollar%7C1&facetInfo= . If you really are very dirt poor with little resources get a piece of pipe 2in in diameter or larger place it in a vice. Then clamp the end of your tubing to the side now as you pull on the other end of the material it will bend around the pipe. Note that this will not be easy it will take a lot of force but has to be slow and controlled force or you will end up with a sub par bend. It is not how you are supposed to do it but it will definitely work. Best of luck to you.

Re: Bending Square aluminium tubing
 

368 did it this year with a pipe bender (I think) and 6063 alloy. 6061 will probably crack.

Re: Bending Square aluminium tubing
 

I've seen the effects of bending 6061 plate with a mandrel/vice setup. I'm not sure of the hardness, but one bend attempt--as I understand it, at the recommended minimum radius--did in fact crack, rather badly. (A slightly more processed plate--we think it was partially annealed--bent easily at a much smaller radius.)

The trick with a closed loop like what you seem to describe is that you have to have a way to get it out of whatever you're bending with after the last bend. Also, you'll probably want to weld/bolt/rivet/otherwise fasten the ends together. Oh... and heat can help you, but you need to be cautious using it, both from the standpoint of "this can set stuff on fire" and that of "this is changing the properties of this metal, do I really want to do that?"

Re: Bending Square aluminium tubing
 

Are you intending to use this as a chassis frame? If so 14" is far to narrow

Re: Bending Square aluminium tubing
 

That's arguable. 14" could work.

EDIT: Wait, I read that as 24". 14" seems a little too thin.

Can it be done without bending? Can you use regular sheet metal?
I would ask 368. They bent some tubing, although I forget how... I even asked them earlier but I've forgotten. They said something about not using a special machine due to size constraints.

Re: Bending Square aluminium tubing
 

Actually, far too long. 14' is what the OP said the distance was.

(I do think he meant 14", but I take what was stated at face value...)

Re: Bending Square aluminium tubing
 

As others have noted, it is possible to bend 1.5" square tubing. But it is not easy unless you have the right machinery, and that is expensive. You also need the right kind of aluminum, and 6061-T6 is not it. Do your homework to find a better material.

Your best bet is cut and re-join using gusset plates at the corners.

That being said, you can make a fixture that will improve your chances of success. The first part is two flat plates to prevent the top and bottom walls of the bend from splaying outward or folding. The second part is filling the tube tightly with dry sand to help maintain even pressure and, again, help prevent folding. The last part is a curved wooden "buck" to bend against to maintain a reasonable radius.

So, this fixture might look like two 12" square pieces of plywood, screwed together through a 1.5" thick piece of wood cut to a curve of about 6" radius, and held tightly in a vise. The sand is held in place with wooden plugs or a few layers of duct tape. Use a large piece of heavy pipe to make the bend, and you need to figure out a way to hold the tube as you pull on it.

Even then, practice first, because that's not trivial to do.

Re: Bending Square aluminium tubing
 

1519 has never bent aluminum box/tubing of that size manually... In 2008 we used 1x1x1/16" box as the curved "tusks" to hold the large trackballs, but these were formed by a machine shop for us. (For a picture of that robot, we have some pictures on our website: http://mechanicalmayhem.org/Mechanic...agegallery.php)

We have also used a pipe bender (vaguely similar to this: http://www.harborfreight.com/1-2-hal...der-94623.html) successfully to bend fairly small (.375-.75") square or round tubing of either aluminum or steel. It's a forming method that can be very useful, but also somewhat imprecise and tedious.

Basically, I'm not sure that it can be done with hand tools or simple fixtures, but machine shops have the equipment to bend tubing profiles far larger than 1.5x1.5. It looks like a fairly simple hydraulic press like this (http://www.harborfreight.com/16-ton-...der-35336.html) can bend round profiles, but I'm not sure how a square profile would behave.

Re: Bending Square aluminium tubing
 

I'm taking a class on using this tomorrow. The bender portion interests me the most. I'll be asking the instructor questions for robot applications. If something is worth sharing, I'll be sure to follow up.

Re: Bending Square aluminium tubing
 

Yes, our team uses a hydraulic tube and pipe bender specifically a pro4 bender from pro bender at this website:

http://www.probender.com/probender/drupal/benders

These types of benders are used by car fabricators to make roll cages and all sorts of neat stuff. There are many other companies that make tubing benders such as JD squared JD2. You can see many of them in operation on youtube. we decided on the pro bender because it is powered by a cheap pneumatic hydraulic ram and you don't have to bolt it to the floor.

These types of benders use dies and roll the tubing through them. They are rotary type benders. This is not the same as a mandrel bender which pulls a mandrel through the inside of the tube so that it does not crush the tube when bending. Hardly anyone has a true mandrel bender except for high performance muffler shops. Too expensive for the average small shop. The pro bender as well as others can bend up to 1-1/2" Square tubing, but you have to buy a 1-1/2" die to do it.

We used 90 degree bends on 6063-T6 1"x1" x .062" tubing for our wings, and about 15 degree bends on 6063-T6 1"x1" x .125" tubing for our collector. An easy job for our bender. There is a science in making multiple bends on a single tube. We use a program called bendtech pro which allows us to draw up the tube, make bending marks, and then make all the bends from one end. You have to calibrate it for the tubing and die you use.

Harbor freight benders are not rotary type and do not put out the same quality of bends.

Remember, these type of benders do crush and deform the tube. The square tubing gets collapsed on the inside by a controlled amount. If I have time tomorrow, I will take a picture of what I am talking about.

If you want to bend 1-1/2" aluminum, I would call the manufacturer of the bender your interested in. Let me know if you have any questions.

1678 and the others have it right, 6061-T6 will snap. We tried it with about a 15 degree bend thinking it was on the mild side and it just snapped in half.

I have a personal project using the bender. Gonna make some tubular control arms for my project car.

Alan
Mentor for Team 368

Re: Bending Square aluminium tubing
 

The problem with bending 1.5 x 1.5 x 0.063 aluminum box tubing will be crushing the profile (it'll likely look squashed when you are done).

To prevent this, fill the entire tube with sand and duct tape the ends closed really well. The sand will prevent the tube when getting crushed when you put it through a tube bender.