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kbmeister
01-07-2003, 02:25 AM
I was wondering, would materials like carbon kevlar or graphite be considered "carbon fiber" under the restricted materials list?

Al Skierkiewicz
01-07-2003, 07:32 AM
Under "exotic materials" section of the rules, I would rule these materials as not allowed. Graphite used as a lubricant could be allowed but it's yucky and conductive.

Paul Copioli
01-07-2003, 07:42 AM
I have to agree with Al on this one. The rules state that if a category under restricted material exists (I.E. Exotic Materials) and an item that fits that category is NOT listed, then it is NOT allowed. Now, some materials could be ambiguous under this rule, but Kevlar reinforced composite and even graphite reinforced composite are as exotic as carbon fiber composite. One that may be very ambiguous is Fiberglass, but I think a very solid arguement can be made that fiberglass is not exotic, but I will follow up with FIRST.

-Paul

Raul
01-07-2003, 07:50 AM
Fiberglass and resin have been on the additional HW list every past year I can remember. I would assume that since it was always legal to use in the past that it classifies it as not exotic.

Paul Copioli
01-07-2003, 07:55 AM
Raul,

I agree. Fiberglass is VERY common.

ChrisH
01-07-2003, 09:46 AM
Carbon fiber and graphite fiber are the same thing. Carbon fiber is on the exotic materials list so any composites using it would be illegal. This is a continuing disappointment to me because making airplanes out of carbon fiber is what I do for a living. I could get as much as I need to build robots for a decade by asking for some obsolete material.

But I also understand WHY they prohibit it. While carbon composites are very strong for their weight, when they to break they shatter. Leaving all kinds of splinters all over the place. No only that, but failure generally occurs without much visual warning. You see the object bending, but there is no yield to tell you to back off.

My co-workers and I regard graphite splinters and minor cuts to be an occupational hazard. If you are going to work with the stuff you just live with it. Cutting and drilling these composites without splintering requires special knowledge and special cutters or drills. These can be very expensive so there would be great temptation NOT to use the proper equipment.

Fiberglass on the other hand is much friendlier. While it too tends to fail suddenly, the remains are not as likely to stab you. While it is somewhat heavier than carbon, it is still lighter than steel and has a similar modulus. Fiberglass can in fact be stronger than carbon, but it is not quite as stiff.

All in all, I think fiberglass makes much more sense for FIRST teams than carbon.

BTW has anybody else noticed that while they put a $ limit on how much you spend for parts for your robot, they did not limit the amount you spend for tooling? Maybe I just noticed because we routinely spend tens of thousands to fabricate tools to make parts worth hundreds.

Greg Ross
01-07-2003, 11:24 AM
Originally posted by ChrisH
...because we routinely spend tens of thousands to fabricate tools to make parts worth hundreds.
That would be at his daytime job. That certainly doesn't describe our team!:yikes: