Non-metallic frame
 

Aside from fiberglass pultrusions, has anyone built a robot out of composite materials? I've built a few boats out of okoume/fiberglass/epoxy composites and have been impressed with the stiffness to weight ratio. I've not been as impressed with the impact resistance, though, but with the new bumper rules this might not be an issue.

I'd be perfectly willing to discuss pros and cons (it would be fun), but I'd really like to hear if anyone has tried it. During the '05 season I tried to get the students to consider custom-made carbon fiber/epoxy tubes for the tetra lifter, but they wussed out. Teen-agers are much too conservative.

Re: Non-metallic frame
 

Yes, I have herd of bots made from polycarbonate, the frame and everything

Re: Non-metallic frame
 

Over the years, we've made our chassis more-often-than-not out of lexan and wood. You can make it nice and stiff if properly designed and cross-braced. Check out pictures of ours from 93-2002, 2004, and 2007.
Also check out WPI's from 2006 as well. Goodluck.

Re: Non-metallic frame
 

Rick, I could've sworn you've made the conservative teenagers line before ;) .

I don't recall teams making a base out of all custom molded fiberglass/carbon fiber; but I have seen some good nonmetallic basese. The Use of polycarbonate by 126/190 has already been mentioned; but some teams like 703 and 1126 use it alongside metal in some years. Rage 173 has also been known for the all Birch (pretty sure it's Birch) Plywood base for years.

A lot of teams last year attempted making ramps from carbon fiber; I don't recall how successful they were, but I don't know if that was the actuation of the ramp/lift or the material itself that didn't work.

Last year, one of my favorite teams, 1717 Made some very, very nice ramps from Foam covered in aluminum sheet.

I know a lot of teams have used composites for manipulators; Over the years several teams have used the stick of carbon fiber hockey sticks as a light COTS arm. Also, not sure if this meets your qualifications, but 330's arm last year was a nice example of mostly nonmetal construction; The arm itself was fiberglass pultrustion and the grabber was plywood on top with lexan on the bottom I believe.

Re: Non-metallic frame
 

Find any picture of any of our past robots and you'll see what he's talking about. Our base is made of 9 ply Baltic Birch plywood.

Re: Non-metallic frame
 

Team 1714 builds almost our whole robot out of polycarbonate. We always have, however this year we stepped it up. The only metal we have in our chassis is the gear boxes, the rest is all polycarb.
Joey

Re: Non-metallic frame
 

Teenagers are so conservative... Thanks a lot:P

Our team, 2083 actually made our arm/lifer out of kevlar(bullet proof, RIGHT ON!!) and it is amazingly tuff. The thing is a total of 20 pounds with motors. Only problem is it takes around 2 weeks to assemble. So if you have plenty of time and money, kevlar makes a great arm. (Note: you must also carve out a foam core for it to be strong.)

Re: Non-metallic frame
 

Uh. Kevlar Weave, when in the right thickness/amounts, can be bullet RESISTANT.

Very true on the foam core part. I've built carbon fiber, fiberglass, and kevlar/carbon weave longboards, and without a foam core, there is NO structure.

Re: Non-metallic frame
 

Pictures? I gotta see this.

Re: Non-metallic frame
 

Don't you people ever forget anything? (In fact, I think I've used it here twice before...)

Re: Non-metallic frame
 

One example from this year that's right close to home from yours truly: 1293.



Their robot this season, R5D5, has a chassis cut from one piece of UHMW, around 1.25" if I remember correctly. There's more to their robot than is pictured (bearing mounts, bumper mounts, etc.), but I'll leave that for them to post (or to show off at Palmetto).

Re: Non-metallic frame
 

In our first year (before the kitbot frame) we just bolted bearing blocks on to a flat sheet of 3/4" plywood. Technically, we had a wooden drive base, I guess. We were going to use 1/2" plywood for the sides and top, but that was a bit heavy, so we went with urethane foam cored fibreglass.

We used the fibreglass on our superstructure the following year and built a wooden arm that probably had a strength/weight ratio higher than any of the aluminum arms that year (we demonstrated it by having two judges stand on a replica of it) and our team's passion for wooden materials was ignited.

The following year we had pulleys turned on the wood lathe from mahogany, bearing blocks cut on the CNC router from maple, and the entire ball shooter mechanism made of baltic birch plywood.... bearings, shafts and such excepted, of course.

Last year our elevator was "all wood"... well, with the exception of some of the hardware, motors and pneumatics, that is.

This year our superstructure is once again wooden, but the plan was to custom build a 6wd chassis out of plywood. That plan got laid by the wayside when the game was announced as the kitbot seemed ideal.

People are always amazed at how much wood we have in our robot... they forget that wood is the original carbon fibre!

Jason

Re: Non-metallic frame
 

If you were in Portland that year (I'm guessing 2005, right?) you might remember Wooden Thunder, which sported an Okoume plywood tower that I built from boat scraps to show students that not everything had to be aluminum. The students bolted it onto the kitbot chassis and it is what went to the tournament. I remember a 'bot with a wooden arm (sounds like the beginning of a joke...) that could well have been yours.

Re: Non-metallic frame
 

1676 is mostly metal, but our gripper is made from a composite consisting of end-grain balsa wood covered with light fiberglass cloth and polyester resin. Very light, incredibly crush-resistant, stiffer than 1/2" CDX plywood too.

Don