Does anyone know if it is something that exists?
I am talking about blocks of carbon fiber that can be machined and then wrapped with cloth.
I imagine it would need to be done with an autoclave and some serious pressure to squeeze the hell out of it.
I have been thinking of doing some parts what would have to bear a load and they would require about an inch to two inches of thickness.
WOW that would be some heavy expensive machining work to cut that stuff.
A friend wants to make a full autococker body out of billet, and all I tell him is we don’t have the capability to accomplish such a feet.
if you find some please posta link, very interested to see what is avalible.
How large of a “part” are you talking about?
Also, how much weight is going to be on this slab?
For me it would be blocks about 16 inches long, 8 inches wide and 2 inches thick with another one at same dimensions but 1 inch thick.
Its not weight its load forces that I dont have the math capabilities to do. Twisting loads and what not.
Just curious as to whether or not it can be done and can it work for my applications
Well, you might want to check into Phenolic sheets (remants are cheaper from a supplier) as they are made with Epoxy resin, have many layers of woven reinforcements and come in different thickness. It is the same stuff that high dollar carb spacers are made from. The only “maybe” drawback is it is a brown in color.
Or, it could be done in many steps with oven cured CF Pre-preg. Just use Nylon peel ply between each 1/4" layer (or so) as it will allow you to crosslink the next 1/4" layer properly during oven curing cycles. But it will not be cheap…as CF Pre-preg (I have been trying to get correct pricing from a local company that will donate it to my job training program, but no luck yet) I have heard is anywhere from $7.00 to $15.00 per square foot and only mil’s thickness!
But I would hate to try and cut that slab unless you have many bandsaw blades.
If you want to pay my class to build a oversize slab for you, we might be able as we have a RVBS and oven cured CF PP in the class right now. But you will have to machine it.
You stated “…blocks of Carbon Fiber that can be machined and wrapped with cloth”, but it is the cloth or reinforcements that makes it strong, not the binding agent. Also, is this going to end up a flat plate or what?
Well I would be wrapping it in twill for looks afterwards.
I might be waaaaaay wrong on this idea but I figured that you would be able to do it if you cut many sheets of cloth and layered them one on top of the other in different directions. compress manualy and squeeze the excess resin out of it. Let it kick and then remove it and heat cure it.
I would be machining these into “triple clamps” for motorcycles. The would have a "pinch cut in them for clamping the forks and I would devise a way to affix the steering stem.
If you can do it with crappy aluminum casting, why not carbon?
The reason I question so hard is that when I worked for the factory superbike teams I use alot of carbon fiber brake pads. They look from appearance to be just like chopped strand matt in looking at them. But they were SOLID as hell and weighed nothing.
Granted they sucked with the technology about 10 years ago when we used them but we tried to make em work!
The new ones are way better and work for the top riders.
Oh and I would be using a manual mill with some type of cutter for plastics, lots of teeth and carefull cutting.
Billet is one of those catch phrases where people are willing to pay more money for even though it is not better. A billet is basically a solid block with the grain oriented in one direction, it’s pretty much the same as wood. If you start cutting into, there will be a lot of weak points. Just imagine cutting notches in a 2x4 stud, it will not be as strongs as before you cut it. A cold forged part is significantly stronger because the grain pattern is forced into the final shape. Good casting would also be better than billet.
Carbon fiber is much the same way. Long continuous fibers are much stronger than little chopped strands. Milling into a carbon fiber block will result in a very weak part and very wasteful use of carbon fiber. If you are planning to make the triple clamp, it is best to mold the entire piece, not easy to do though. From an engineers point of view, I wouldn’t go making a structual part like that especially if you don’t know how to analyze the stresses. Composite materials are a bitch to figure out stresses. A triple clamp is one of the more highly stressed parts on a motorcycle. If that breaks…
Just because something is solid doesn’t mean it is strong. Take concrete for instance. It’s strong under compression, but apply a tensile load to it, it’l snap really easily.
This I understand but if they are doing brakes with it it must have something solid to it.
Not too mention I have seen a few rearsets and what not out of it.
Just want to experiment with it all.
Oh and I find that carbon is alot cheaper than running billet magnesium seeing as a cnc machine needs to be kept super clean and it has to cut waaaaaay slower to avoid the fire potential.
Ive done the mag thing and its a bore really…just looking to come up with something different and see what I can get out of it.
Oh and have any of you seen the carbon fiber piston that they might have developed for real use? Looked cool but I have doubts about it surviving the loads and heat.
I haven’t seen a carbon fibre piston but I have seen a carbon one. Which makes sense to me as I wouldn’t think they would have a resin that could stand the heat.
Carbon fiber brake rotor composition is as secretive as what goes on at Area 51. You won’t be able to find out what goes into them. I can speculate it is formed under really high pressures.
But like I said before, machining out a block of carbon fiber goes against the basic principles of carbon fiber construction. Any time you cut into carbon fiber, you will severely weaken the part.
If you want to make a triple clamp, a better and stronger method is to mold the entire piece and glue in inserts where it attaches to the fork. Machine out a mold and use a high pressure bladder. Insert material will be dependant on what it will be attached to, to prevent galvanic corrosion. Remember a hollow part of the same weight as a solid part will be stronger.
Your being really small minded scooter.
Because you cant access the information it surely doesnt mean I cant access it.
Lets not forget I left alot of friends in high places. I will make a few calls in the next few weeks and see what information I can come up with.
Now maybe I can just make a rearset or triple clamp or clipon out of carbon using a molding method but seeing as I dont really have that much experience with that type of molding I figured my talent in machining would be a better apt way about it.
Not being small minded, I’m just looking at the application from the mechanical engineer’s point of view.
People go to great lengths to avoid cutting or drilling into carbon fiber components because it weakens the part. Molding a hole is much stronger than drilling a hole because you are keeping the fibers intact. By machining the part out of one piece, you will have to overbuild it in order to compensate for the strength loss thereby adding more weight. Which pretty much defeats the purpose of making it out of carbon fiber.
With a triple clamp design, the huge holes you have to cut for the forks would have to have a lot of material around it because you are breaking the fibers up into individual pieces. Individual fibers are fine on a brake pad because it is under a compressive load. Even concrete is really strong under compression. But with a triple clamp and the forces applied to them, you are not under compression but under tension. Small fibers are not going to be able to handle the loads. If you want to do a simple test, grab a carbon fiber brake pad (just the carbon portion), drill a hole through it. The bolt a handle onto the pad, clamp the pad in a vice and start applying a force to it. Then do the same with an aluminum piece with the same dimensions.
I understand what your saying completely but I am going to research it a tad bit more.
If it can be done I will do it, I might have to make the part with the holes in it but that adds to the complexity of the design. Something I may have to consider eventually and figure it out.
Its more just to see what all I can actually do and not do without having million dollar equipment.
I do appreciate your replies as you are taking the time to look at it and ponder feasibility.