What is Filament winding usually used for?
Can I use it to make cold air intake tubes? Or am I better off making a two part mold of a CAI and reproducing it in two halves?
Filament winding is typically used for cylindrical parts, like driveshafts or pressure vessels. I don’t think it’s used for parts with that have curvature like intake tubes. Also it requires a filament winding machine, I’ve never heard of anyone filament winding purely by hand, although I suppose it can be done.
^ what he said…mucho bucks for filament winding machine, most typical applications are straight-pipes etc…you’d be better off to make a split mould of the intake pipe and glue them together, other alternative is to wrap it with a carbon sock and infuse the part to the carbon depending on the route the pipe takes.
Yes… We’ll most likely have to just make a two part mold.
If they make tubes using the filament winding technique. How do they separate the tubes from the tube that they mold around?
Sometimes they don’t remove it at all and just leave it in the middle. If they do remove it you can use collapsible molds, which is what is used for the 787, a six part inner mandrel.
Or you can do what I did, which was “freeze” the whole thing, then bang the aluminum mandrel on the ground until it popped loose.
Now that’s a good idea canyon :). Any pics of that? If possible.
For tubes, remove the mandrel the standard way. Pull it out, or freeze and pull out. Ive had luck not doing anything to my tube mandrels and just pulling the tube off. Only 12" long though. as for tanks, many are wrapped around a thin steel, or plastic liner. Then you can make sure the bottom and top are reinforced. I know SOME composite tanks are glued together. Propane tanks are…however, they have a different way of manufacture completely. (youtube it, I think How It’s Made did one)
You can also wind a high density polystyrene mandrel with fiber/epoxy and manually or chemically remove the foam. Some complex shapes are being done this way. The foam mandrels are quickly cut on a CNC lathe.
Here’s a cutaway and failed fiber wrapped paintball cylinder for your reference.
Filament winding:
Mostly a round object or something that can closely be called “round” is fixed into a rotating device. A roving or any other suitable fiber pack (even CSM, multiaxials, etc) are wound on the pipe. Resin is added by running the fiber through a fiber bath, or is sprayed on in the process.
In the how-its-made video a fiber pack is RTM-ed, which is feasable for smaller parts.
I have seen people filament wind 30ft diameter silos (in situ, as transport of the silo would be a problem). Also, the silos are surprisingly thin. The bottom is usually made with hand laminate, over a concrete base, the top is constructed from segments, glued together. The walls are made progressively thinner near the top.
I also have had a customer filament winding by hand (motorcycle exhausts) on a very simple machine, made from wood. It was bench top, and he used a revolving threaded rod to nicely guide the fiber. Impregnation was with a brush of resin. After winding and adding some fabric, he added a carefully cut piece of carbon, on a teflon sheet, spreaded out the air bubbles, ad ready he was!
The Britten V1000 motorcycle used hand wound filament structures in the frame/chassis and suspension parts (rear swing arm and front wishbone - the bike bike doesn’t have conventional forks). There was a documentary made about it called “The Britten Bike Story”. In the video you can see them wetting out the tow with a brush but you don’t get to see the layup unfortnately.
