Thin walled aluminum tube bending 1

[stevec77]

Please look at the attached drawing and tell me if and how to get a tube to bend as shown? It has to be able to be a production run. It will be used as mechanical tube not pressure.
Thank you,

Steve

 

[MadMango]

It's possible to be done, but the top radii are a bit sharp. The walls of your rectangular tube will crush-in at those corners. If that's not a concern, any shop with a tube bender can make this. If the interior of your tube is the important bit, you may want a different manufacturing approach. Some more details might be helpful for others to provide a more complete answer.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[rb1957]

are dim'ns ft or in ?

google specialised tube bend manuf.

as noted ablove, are crushed sides a problem ?

you may need to form in O-condition material, and HT as req'd later.

you may need "non-traditional" tube ending. ie, instead of using a regualr tube bending machine, you might form a wide circular bend and then flatten it to make the sides and the end.

i hope two decimal places on the angles is just a cad thing (and not a requirement) ... i doubt they're achievable.

 

[stevec77]

Thank you for your interest. Here are some specifics such as we know them.

We are leaving the wall size of this tube open in case you tell us that it can be done at a certain size but not another. Here is some background that should help you understand the forces it will be subject to.

1. This is going to be a component of a mass produced consumer device. It is very important that it be as light weight and inexpensive as possible.

2. This is to serve as a frame & stand component of a consumer device we are designing for manufacture.

3. The upper section (squared head) will support an enclosure weighing approximately 1.0 lbs. The lower section of the frame/stand will attach to a rectangle shaped base 3" wide x 12" long x 3 inches high, and weighted with 2 lbs. The frame, as drawn, will attach to one end of the base. Picture a capital letter L.

4. It is not intended to be a handle per say. Its intended function is to support the 1 pound of weight at the top. However, we know that the end user will pick it up by the top and carry it around occasionally, when relocating it. The base, when being moved, will subject the frame to additional stress and torque. Therefore, it must support the base as it is being transported without twisting or buckling.

In your opinion and experience, is it possible to form this shape in a tube that also tries to meet the conditions described above? If yes, we will secure an mechanical engineer and develop more specifics.

Thank you again for taking the time to answer our question.

Steve Chayer
Chayer Design

 

[rb1957]

i'd talk to a specialised tube manufacture, they'll know much more about the process, what can be achieved, what ca't, and what'll cost you.

why metal tube (my assumption) ? why not injection moulded plastic ?? a how different forming process, a how different formability, producability, ...

 

[stevec77]

Dear RB, All good questions. We are looking at injection molding to accomplish this function in less expensive versions but want to introduce it at the higher end of what we hope this market will want. We are considering changing the shape of the top to more rounded but not a circle probably the fat end of a drop of water.

The forming process will have to lend itself to mass production to keep costs in line. We are looking at multiple processes including hydro forming which appears to be very slow.

Steve

 

[rb1957]

the 1/2 circle shape would be an intermediate forming stage ... the circle could be flattened to produce the shape you 're looking for.

 

[stevec77]

TV, please tell me what the term flattened means?

Steve

 

[Cockroach]

The old fashion way, heat it up at the bend and use the proper radius specification.

Regards,
Cockroach

 

[IRstuff]

One option may be to fill with sand before bending. The sand is supposed to prevent the tube from collapsing. Not exactly a mass production process...

TTFN
faq731-376

 

[ornerynorsk]

What's your wall thickness and preferred alloy?

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[stevec77]

Ornery, The wall thickness is still open in the event an engineer says it should be X to accomplish the bends but we were thinking somewhere in the 1mm range. The alloy is pen too recommendation.

Production is key. It has to be mass produced to keep cost as low as possible.

Steve

 

[MiketheEngineer]

Yes - I have used sand to do something like this.. Slow - but it usually works OK

 

[rb1957]

ok, for me, "tube bending" implies putting the tube into a tube bending machine, with a restraint, a radius block, and an actuator to load the tube.

the small radius and the overall shape look to me to be hard to bend in a traditional machine, but ask a specialist.

it seemed to me that a non-traditional approach might get what you're looking for ... bend the tube in a large semi-circle, and then with some sort of press flatten the semi-circle into the three flat side of the end.