I've been looking at different rib designs for a potential project that has been bouncing around in my head. In sheet metal, putting the flange on a rib blank... without deforming or "potato-chip-ing" the rib because of the excess metal... is of course the primary concern.
Would prefer to form the rib flange without fluting, and without cutting relief notches. Production airplane companies would of course hydroform or 'rubber block form' the ribs and all would be well. But I'm not investing in that type of tooling or going to a hydroform shop if I can help it.
I'm also aware of the "Thorp method" of hammering the flange with a backing block, but I'm trying to see if another method will be less effort.
I have seen videos of automotive sheet metal shops using a bead roller tool, with a flange "tipping" die wheel set. Without fail, they run the curved piece through the bead roller but then they have to go over to the shrinker and beat the crap out of the flange to take the deformation out. That would weaken the flange, which is exactly what I'm trying to avoid.
But then, I saw a video or two of a simple hand held flange roller tool that apparently makes a 90 degree flange on a curved edge, without deforming the part. The operator gently rolls this tool back and forth many times, and for some reason it does not appear to deform or warp the flat piece to require "straightening".
Which brings me to the questions:
1) Can anyone explain why the large heavy equipment bead roller machines (whether powered or hand operated) seem to warp the panel and require straightening, but it appears the little handheld roller tool can put an unbroken, non-wrinkled flange on the curved edge of a flat sheet without deforming the part on the other axis?
2) Have any of you made wing rib structural rivet flanges with one of these tools?
(I know these roller style tools are sold for flanging the lightening holes in ribs, but I'm talking about using this type of tool to put a skin riveting flange on a flat blank, without having to 'shrink' it later)
The video here shows this tool, the flanging starts at about 0:30
Would prefer to form the rib flange without fluting, and without cutting relief notches. Production airplane companies would of course hydroform or 'rubber block form' the ribs and all would be well. But I'm not investing in that type of tooling or going to a hydroform shop if I can help it.
I'm also aware of the "Thorp method" of hammering the flange with a backing block, but I'm trying to see if another method will be less effort.
I have seen videos of automotive sheet metal shops using a bead roller tool, with a flange "tipping" die wheel set. Without fail, they run the curved piece through the bead roller but then they have to go over to the shrinker and beat the crap out of the flange to take the deformation out. That would weaken the flange, which is exactly what I'm trying to avoid.
But then, I saw a video or two of a simple hand held flange roller tool that apparently makes a 90 degree flange on a curved edge, without deforming the part. The operator gently rolls this tool back and forth many times, and for some reason it does not appear to deform or warp the flat piece to require "straightening".
Which brings me to the questions:
1) Can anyone explain why the large heavy equipment bead roller machines (whether powered or hand operated) seem to warp the panel and require straightening, but it appears the little handheld roller tool can put an unbroken, non-wrinkled flange on the curved edge of a flat sheet without deforming the part on the other axis?
2) Have any of you made wing rib structural rivet flanges with one of these tools?
(I know these roller style tools are sold for flanging the lightening holes in ribs, but I'm talking about using this type of tool to put a skin riveting flange on a flat blank, without having to 'shrink' it later)
The video here shows this tool, the flanging starts at about 0:30
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