Edge rolling a cylinder for encapsulation force question

[RoarkS]

As shown in my model (sectioned in half for explanation), using a die (current plan anyway), I need to roll this tube over on itself to encapsulate the contents.

The tube is made of 1010 steel .015" with .004" Cu plating.

Anyone out there a little more familiar with sheet metal able to help me at least ball park the amount of force I need to design the press?

Equations would be great.

Also... to calculate the length of tube to get the right amount to roll over, I just used two models (rolled and pre-rolled) and compared the masses until I got the right length with the same mass as the crimped one. Is that reasonable?

Figure the die will be acting collinear with the centerline of the assembly. The die will be tool steel (possibly carbide) pressing on the bronze plating.

Just some thinking on my part...
I'm guessing that friction between the die and part might be important so I looked that up. Friction coefficient of .16 to .36 depending on lubrication. I'm unsure if that is completely negligible/pointless when compared to the force needed to bend over the tube.

Thanks!

 

[KENAT]

You intend just pressing it over, in some applications a rotary element to produce an effect a bit like spinning can help - but I'm afraid I'm not an expert.

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[RoarkS]

I had thought of that... it's not out of possibility, it's just pressing it would be the simplest solution for the assembly machine. There are about 5 other processes the assembly machine needs to do, which are press motions... except the last step which is a rotary... huh. I'll have to think about that. Thanks for the idea.

 

[RoarkS]

Anyone have any key words what this process might be called? Im sure there has to be information on it somewhere... I just don't know what to look for.

 

[MikeHalloran]

The process is called 'swaging'. The verb is 'swage'.
The tooling to do an axial swage is pretty simple.
Rotary swaging is also mature technology, capable of extreme deformation, beyond what you probably need.



Mike Halloran
Pembroke Pines, FL, USA

 

[KENAT]

Yep swaging is the term we used in the UK, wasn't sure if it was a universal term. Previous employer used to do it on a type of shot gun cartridge (well, the vendor that supplied the cartridges did it, but you get the point).

http://en.wikipedia.org/wiki/Swaging

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[chicopee]

Whatever cold forming process you utilize, I can forsee several problems such as the rounded end having waviness, the center hole not being uniform and the shell buckling if swashing. I have not seen any formula that would address your situation, altho, there are formulae for shearing bending and the like.
Taking about cartridges, we used to make brass 25mm cartridge during the vietnam conflict, and we had a series of dies and heat treatment to make the finish product. Granted we started with brass tubing thicker that what you have.
In your case with thin wall tubing, your process will not be an easy task. I suggest that you you do trial and error tests.

 

[unclesyd]

Depending on your quantities i would contact Grant Riveters
concerning the possibility of using an orbital riveting hype machine to resolve your problem. You could either buy the machine or contract the work. out The last time I checked there were a lot of these machines on the excess machinery market.

http://www.orbitforming.com/

 

[RoarkS]

AWESOME IDEA!