Bead Rolling Standards 1

[aulrich]

Hi all,

We have some sheet metal fabrications made of 10 GA steel. Because there are some pretty large flat pieces, the structure lacks stiffness in several areas.

Someone here suggested bead rolling these large flat pieces to increase the stiffness. This may well work, but I have not had any success in locating a standard or even basic bead rolling sizes that are typically used.

I would like to model this in CAD so that I can do some basic FEA, but without any guide as to what's possible with a bead roller, I'm not sure where to start.

Anyone have experience in this?

Regards,

Andri

 

[telecomguy]

I would say just about anything's possible with the right tooling. I would start with my regular sheetmetal shop to find out what their capabilities are. Otherwise, your sources may be limited. Most bead roller tooling I find is for lighter guages of steel.

http://xternal.me

 

[StrykerTECH]

I think you may be barking up the wrong tree with that one. We used 10ga for some of our large enclosures, we have run into the same problem, with lack of rigidity. We found the best method to stiffen up the box was to shoot a couple weld studs on it and just bolt on a stiffening angle, something like an 1.5" L. Actually turns out we down gauged the product to 12ga and that saved us the cost of the angle with out sacrificing stiffness. On some of our real small stuff, we do bead rolling but that is like 18ga max, mostly 20ga and 22ga. Fundamentally, we can roll about a 1/16" bead into 22ga, to get the equivalent stiffness enhancement you would have to roll bead in .25", with that much material deformation, it may be stiffer but it won't be flat. Plus tooling will be insanely expensive.


StrykerTECH Engineering Staff

http://www.stryker-tech.com/

 

[aulrich]

I went ahead and emailed the shop to see what they can do. I am concerned that they won't be able to bead roll material that thick, as StrykerTECH mentioned.

Also of concern is that the material will likely not be very flat after bead rolling, especially a heavy gauge and a large bead.

I may explore different ways to stiffen the sheets - perhaps bolting or even welding on some angle iron will be the easiest.

Thanks guys!

Andri

 

[ornerynorsk]

Another method that the HVAC industry uses for stiffening and expansion purposes in large sheetmetal ductwork is to brake a very shallow bend in an X pattern across the sheet. As you mentioned, flatness will suffer as a result, and might preclude its use if flatness is critical to your application.

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.

 

[dhengr]

aulrich
Can you break-form a few crossed creases in the sheet to conform with its final shape, so they look intentional? You could just stitch weld crossed pieces of .125" x .75" bar stock to the sheet, again in an intentional configuration. The crossed stiffeners usually stiffen a rectangular panel, both torsionally and for out of plain movement, better than a stiffener which is parallel to one of the side.

 

[aulrich]

ornerynorsk and dhengr,

I need the sheet to be pretty flat, so brake-forming a shallow bend in a X pattern is probably out of the question. The sheet is actually the side of a centrifugal fan housing/volute, so it's not square or even rectangular in shape.

The shop says that they currently only have equipment/tooling for bead rolling 16 GA max, but probably can expand their capabilities to handle thicker materials if that's what is required.
The shop in this case is the customers - same customer we are designing this unit for, so if we recommend bead rolling these sheets, they will find a way to get it done. That being said, there are surely more cost effective and simpler ways to stiffen these sheets, some of which have already been suggested by you all.

Thanks,

Andri

 

[TheTick]

I have never seen a standard for this. If there is one, none of my vendors or past employers uses it.

 

[tbuelna]

aulrich,

If you have the time and the interest in reading up on the engineering principles behind metal forming operations (like bead rolling) here's a great technical reference.

You did not mention the specific reason for adding stiffeners to your panel, but I'll assume it's to reduce noise rather than to address a stress issue. As others noted, with 10ga steel, roll forming beads is probably not practical. Stitch welding stringers to the panel would get the job done, but it would actually be costly for large production quantities. And frankly, simply welding some pieces of angle iron to your panel is not an elegant solution.

If your budget permits, I would suggest you consider putting a slight convex/concave curvature into your panel center area to increase its stiffness using hydroforming. The cost for hydroforming the panels would probably be competitive with welding on stringers if you are making more than a couple dozen parts. The hydroform tool cost for such a simple part shape would likely be quite modest. The hydroformed panel would also be far easier on the eyes.

Hope that helps.
Terry