Manufacturing of Carbon Fibre Shafts
Manufacturing of Carbon Fibre Shafts
(OP)
I wonder if anyone can give some clue about manufacturing methods of highly loaded carbon fibre shafts other than winding. I have heard about "rolling" in the manufacturing of skiing poles. Why is not that used in manufacturing of shafts. It is incredibly much cheaper than filamnet winding.
Thanks for any clues.
Thanks for any clues.





RE: Manufacturing of Carbon Fibre Shafts
If you do the same thing with a particularly dull wheel, you can swage the tube down by a few mm with ease. You can then displace the wheel axially by a few mm and repeat the process, and end up with a tube that's longer than the one you started with, smaller in outside diameter, less thick, and because of work hardening, stronger.
Several variations of such roller swaging or rotary swaging also work on steel tube and on aluminum tube, because of their ductility.
Carbon fibre is brittle, not ductile, so the swaging process is unlikely to produce satisfactory results on it. Carbon fibre, actually fibre reinforced polymer, is so brittle that it can be formed only in a-stage (wet) or b-stage (sticky), i.e. before the polymer has cross- linked fully.
Don't give up. If you _do_ find a fast fabrication method for frp, you'll be able to retire very young and very wealthy.
Mike Halloran
Pembroke Pines, FL, USA
RE: Manufacturing of Carbon Fibre Shafts
I think the op is referring to the technique of rolling pre-preg CF (or whatever) around a mandrel, taping it up with release tape and curing it, then removing the steel mandrel. Used for low volume composite tubing (e.g. Hardy's fly fishing rods, Alnwick, England - take a mortgage out!)
Whereas filament winding is used for high volume stuff (e.g. Golf club shafts) or when maximum performance is required due to the lower resin/filament ratio possible.
Cheers
Harry
RE: Manufacturing of Carbon Fibre Shafts
Mike Halloran
Pembroke Pines, FL, USA
RE: Manufacturing of Carbon Fibre Shafts
My question is: Are there any hidden pitfalls by using the rolling method for structuraly loaded shafts. This is a drive shaft, and so we need shear strength from torque input and bending stiffness to prevent vibration.
Thanks
RE: Manufacturing of Carbon Fibre Shafts
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RE: Manufacturing of Carbon Fibre Shafts
RE: Manufacturing of Carbon Fibre Shafts
Yes, I am aware of the discontinuity either along the length or at 45 degr. But you would normally roll several layers of prepreg mats and thus place the seam at different circumferential angles. This will, of course, require some control of your process, but still. I am not convinced. Do we have anyone out there who can report severe problems with highly loaded rolled shafts?
Investing in a filament wound machine is extremely expensive and for low volume production I am looking for better utilisation of my cash.
RE: Manufacturing of Carbon Fibre Shafts
Izax, I never said it couldn't be done, just that the tube wall will need to be thicker (several layers of cloth or tape pre-preg, as you noted). FWIW, I have seen torque tubes made with only two passes of very closely spaced filaments (at +45 and -45), laid down as tapes but in a continuous wind. That's awfully thin, but they work, and carry a lot of torque for the weight.