I want to bend 13mm OD with 1mm wall thickness aluminum pipe like attached picture.

Because of its small bending radius I have problems. It gets wrinkled or torned.

Is there anyone have experience on bending small tubes? Or any idea on this topic?

I have seen people who bend small tubing fill the tube with sand before bending to keep the problems you mentioned from happening.

It might work for you.

Jerry

Not sure what the radius is..looks like 7 or 8mm.....Not sure if you are trying to manually bend this or if you have a pneumatic/hydraulic bender (similar to what is used in automotive shops to bend exhaust pipe).....I believe the key is to make sure that the tubing you are bending is in a soft state (annealed)....usually the outside bend area is supported and a mandrel is slowly pushed into the bend area....gotta lube the parts to reduce the friction....If manually bending...then the sand method or an awfully large bend radius is required.

I think I remember seeing tubing being bent with what seemed like a tight coiled spring around the bend area. Not sure if this helps.

After reading Dustin's Post it occurred to me that a coiled spring could also possibly be inserted INSIDE the tubing also for support.

Might be difficult to remove though. Also might work.
Jerry

than you for all suggestions.

Do you have any photo or video about bending pipe with any hand tool?

12 mm - 29 mm Manual bender with video
http://www.vansantent.com/model_3_bender.htm

6 mm - 10 mm Manual bender
http://www.eastwoodco.com/shopping/search/searchresultsmain.jsp?affiliate=1&fresh=1&searchType=advanced&RS=1&keyword=tubing,brake,bender

Jerry

For that tubing you want a swagelock tubing bender. They are expensive, but worth it. It works well with copper, steel and stainless steel tubing. I doesn't kink tear or crush the tubing. It's a handheld mandrel bender. You would need the 1/2 inch model for 13mm tubing.

http://www.swagelok.com/product.asp?tp=109&ct=818&tpd=Addnl+Products+%2D+Tools++++++++++++++++++++++++++++&ctd=Tube+Benders&bigp=CPH1146A%2DVS%2Ejpg&nump=9&group=ADDNLPRODUCTS&GroupDesc=

What you are trying to do, end up with a smooth entry and exit from the curve on a small radius is very difficult. The usefulness of springs and sand runs out quickly when the radius is tight and aesthetics are important.

I needed a similar bend in smaller dia. copper, which, I'm guessing is easier than al. The problem is that it is really hard to avoid kinks or material build up along the leading edge. I've attached drawings and whatnot for a universal bender of my own design. There are two features to it 1) the former for the outside is linear and follows the pipe around the curve (circular rollers tend to plow up material along the leading edge), and 2) the traveling roller is on a cam so that you can tightly pinch the tube between the two formers.

It has since been built and works fairly well, although it was only designed for up to 3/8 copper. It will bend an inside radius almost to the tube dia. No rep and warranty on the drawings, but I think they are pretty close. There is also a tube straightening mill I did as well. Both look real nice and sit in a drawer with a 10^-8 duty cycle :)

Mcgyver....well I don't know if you got everything covered.....but, darn that is pretty impressive documentation. Thanks for sharing!

thank you for sharing your knowlage and work

thx & you're welcome. Viper i would have included photo's to, but don't the camera this week!

Better late than never?

I think someone touched on this - your aluminum tubing has to be T-0 or T-1 temper designation if you wish to bend it. Typically, the aluminum you buy is either T-5, T-6 or some variation and will fracture when bent. T-0 is custom ordered stuff - not normally available. T-0 is completely annealed and will bend easily. All aluminum will eventually reach a T-5 condition on it's own - even the T-6 material.

Sorry for being late! Is the party over?

Scott

is it possible to anneal t5 or t6 aluminum tube easily?

I think one way is heating tube below melting temperature leave it cool slowly.

if this is true method for annealing. how long time should I keep tube hot, what should temperature be? how should I cool it?

Or what is annealing process for aluminum tube?

Look at this site - you'll have some reading to do, but it has very good information:

http://www.unitedaluminum.com/faq.php

Scott

I have been trying over half a year to bend tight Radi with aluminum, the sand trick is crap the aluminum just cracks on the OD of the bend the springs work kinda IF you stick the spring inside but then you destoy the spring trying to get it out.

I really hope someone can give a more straight forward answer as to what is needed to get aluminum bends in tight radi correctly. Like 180's

many here are more knowledgable than I on the subject, but AL has a bad reputation for cracking from forming, bending etc, some alloys are worse than others. not sure if you can soften it mid bend like copper based alloys or whether bending it hot improves things.

I was at a place last week were they had perfect, very tight 180 bends in copper. Now i know its easy to bend copper, but these were to an inside radius that looked around the tube dia and were flawless. To my query, they said they are filled with lead and kept hot, just below the melting point of the lead. Not sure I want to try that trick at home with lead fumes etc. at a much cooler temp you could use the cerro metal which i've heard works.

I got copper down. But this aluminum is a pain. I can not beleive no one makes atleast a aluminum 90 degree fitting like copper plumber fitting ot a 180 further more. If they do its either over the size I need or threaded and/ or not tight enuff. LOL I would pay someone to make this part hands down. I need something like this REAL BAD.

T-0 temper and mandrel bending - these are required for bending tight radii in Al tubing.

Scott

right but to bend 5/8" with about 1/4 ID?

I haven't tried this my self but picked it up from the model engineering people. This idea is similar to the use of lead described above and is used extensively on copper and brass tubing. The method involves the use of low temperature metal alloys, that melt around the boiling point of water. You will want to get the type that has little or no shrinkage.

It is realitively simple in that you heat up the alloy, pour it in the tube and wait for it to harden. Then make use of a good quality bender. Of course this idea came from people making use of entirely different metals.

As to the use of aluminum, the first thing that comes to mind is is it absolutely required? Sometimes it is better to choose the materials for workability if at all possible. I know this is a different approach but some times getting to the end of the project has to take over.

With the aluminum everyone has already mentioned the tempering of the alloy but I do wonder if you have experimented with different alloys? Also has one considered a cast part? This seems like almsot the ideal part for lost wax. Again casting is a bit like throwing in the towel as far as bending aluminum goes but you might end up with a better product. You would need to make some mold or patterns and cores. Your wall thicknesses might go up a bit. The big advantage with casting is that you have the potential to do so in many alloys and metals.

Dave

I have no prob doing casting but would have no idea as to what is the best way to goabout it with a U shapped core etc. I have no idea as to casting a part like this. If anyone can bend a part like this or cast a part like this I am willing to pay.

I have no prob doing casting but would have no idea as to what is the best way to goabout it with a U shapped core etc. I have no idea as to casting a part like this. If anyone can bend a part like this or cast a part like this I am willing to pay.


I would put in a call to a few of the local distributors of aluminum tubing and ask them to direct your needs as to alloy and/or bending apparatus.

Maybe if you know who produced the sample posted above. Call and compliment them on how impressed you are with the bends in their parts and see if they will offer assistance in your project( for a different application of course). If it is direct competition, then I can see some resistance to lend help.

I don't see what real benefits the 6000 series alloys will gain for the part if it cannot be worked easily. There are other alloys in the 3000 and 5000 series that have high ductility and bend much better. Letting the industry leaders lead, should put you further ahead. They have a greater amount of sector exposure to get their customer where they are going.

You mentioned heavy wall tubing. I would think that to help as long as the material elongation works in your favor for tight bend radius.

DC

Do you have any dimensioned drawings for the part? What's possible depends a whole lot on the size of the thing and how much material is involved, as well as cosmetic requirements and dimension tolerances.

I can think of a couple of approaches for casting but whether they'd fit the criteria for the part is impossible to say without any info.

If you're ready to farm it out, have you considered having it made as a weldment of stamped shells (split along the plane of the radius)?


Tiger

:)

My experience was with die casting a long time ago. That process would not work for this part!

Depending on what your needs are I would imagine that you could do a sand casting with a core. The core would be comples and probably fragile for such a smal part. The core molds would also be complex. There would be alot of work going into this before you even had a part.

Consider a lost wax process also which might be a bit easier.

A hard mold would be very complex if this is a low production rate item. It might be useful to consider though.

Dave