is fiberglass legal to use on a first robot?

[Skute327]

I was wondering if fiberglass is allowed to be used on a first robot. If so, does anyone know if it's a good building material or just messy and problematic. Thanks for any help.

[Cory]

So long as you eliminate any sharp edges, you should be fine.

[mechanicalbrain]

Yeah its legal as of last year. As to messiness.... well i wouldn't recommend doing it yourself. Its not nearly as easy as something out of Home Depot would have you believe. If you want to do your frame then buy premade through the internet. If you want something like a skin (shell) I would still recommend going through the internet but its going to cost. Fiberglass has a decent strength to weight ratio. It won't bend but if you get hit hard it will chip and if your hit REAL hard its possible to shatter. Go with 1/8 (maybe 1/4) inch hollow tubing if you want to make a frame. Even then im not an expert. Contact a company and ask them.

[Wetzel]

Originally Posted by Skute327

I was wondering if fiberglass is allowed to be used on a first robot. If so, does anyone know if it's a good building material or just messy and problematic. Thanks for any help.

It is not a good material for a bumper. Materials have different strengths and weakness for different applications. Figure out what material properties you need and then decide upon a material.

Wetzel

[mechanicalbrain]

Something like this would be good. But you probabely want to do a square tube.

[Beth Sweet]

And just as a precaution, the rules from last year don't always apply to this year so be sure to read the rulebook before going out and buying a bunch of fiberglass! (oh, and be sure to wear gloves and keep dogs away from it... long story...)

[Cory]

Originally Posted by Beth Sweet

(oh, and be sure to wear gloves and keep dogs away from it... long story...)

Nothing is worse than fiberglass splinters stuck in you.

[mechanicalbrain]

How about forge heated metal? OK yeah that picture of the tubing I posted... I played with it. It will take a hammer blow (as much as I was willing to dare). So after looking at it I would say don't make it. It seems like allot of trouble to make.

[Jay H 237]

You can also mill the extruded fiberglass if needed. Just set up a Shop-Vac with the wand near the endmill. It's only messy if you allow it to be.

We used extruded fiberglass for arms back in 2000 but they never made the final cut. During the sixth week we found a problem (you know how that's always the best time to find problems ) with our arm, not related to the use of the fiberglass, that caused them to be scrapped. Due to the cost and time constriant we didn't order more and went with extruded aluminum we had on hand. I don't have any photos of those arms otherwise I would have attached one.

[N7UJJ]

We've been using extruded fiberglass and Lexan for three years. It's very easy to work and simple tools will do. Extremely strong for the weight.
Non metallic so it is transparent to the radio waves and no grounding or shorting problems due to a metal frame.

Videos at http://www.phxhs.k12.az.us/education..._id=1127872327

we use it on our ROV too.

Great stuff

[KenWittlief]

working with fiberglass (mat and resin) is something everyone should tinker with at some point

its really incredible stuff, and you can do things with it that are much more difficult with any other material

but like all things, it has ideal applications, and bad applications.

[Gdeaver]

The material you want to use is fiberglass pultrusuions. They come in the shapes that aluminum does. !/8" wall is what we used but it comes in thicker walls. Mcmaster-Carr sells it. The common pultrusions are fiberglass (e glass) and polyester resin. You can also find pultrusions made with vinyl ester resin. It's a little stronger and more expensive. Team 104 used this for our arm in 2004 and 2005. You can't use the same methods with pultrusionas as with metal. As a rule do not drill holes to mount thing on pultrusions. Clamp them on. Bolts, bearings and other fasteners can be set in the ends for mounting by using epoxy and chopped fiber (carbon or fiberglass). Some teams have used birch ply wood in the construction for cost savings. If you laminate a layer of 6 OZ s glass on both sides of the plywood the result is very strong robot covering at a fraction of the cost of polycarbonate. There are all kinds of uses for fiberglass and composite techniques on first robots. Easy to do, only requires hand tools But there is a little learning curve. Great for fall practice. as a general rule a composite design can save about 25% the weight of an equivalent aluminum part.

[ngreen]

We used fiberglass unistrut on this years robot for the elevator lift and arm. Great material. Saved us a ton of weight and stong enough in testing to hold at least 4-5 tetras at 5-6 feet or at least one mentor trying to break it. Look at 1108 Teaser #1 and #2 to see our fiberglass or I'm sure you can find a competition picture somewhere.

[mechanicalbrain]

Originally Posted by ngreen

We used fiberglass unistrut on this years robot for the elevator lift and arm. Great material. Saved us a ton of weight and stong enough in testing to hold at least 4-5 tetras at 5-6 feet or at least one mentor trying to break it. Look at 1108 Teaser #1 and #2 to see our fiberglass or I'm sure you can find a competition picture somewhere.

Please keep in mind the different types of strengths. While it can take weight consider that if they make something like their entire frame out of this they might want a padding to keep from chipping and splintering.

[Gdeaver]

With composite structures the orientation of the fibers affect it's characteristics. One problem with pultrusions is the large majority of fibers are in the length direction. Because of this point impacts are a problem with Pultrusions. This can be partially addressed by filling the pultrusion with 2 lb, 2 part expanding foam. With pultrusions a good way to increase the point impact strength and increase the load bearing capacity is with tube in tube construction. We took a 2" 1/8 wall and a 1" 1/8 square tube pultrusion. The 1" was inserted in the 2". The space between the 2 on one end was filled with epoxy and chopped carbon fiber for 4" and bolts where set in the epoxy to mount the hinge hardware. The space between the 2 tubes was then filled with the 2 part foam with in 6" of the other end and then that end was filled with epoxy fiber mixture. The resulting structure Has point impact resistance and is stronger than going to heavy wall units and is still very light. With composite work I would strongly recommend using an amine laminating epoxy and not polyester resins. The surface hardness and strength is much better with epoxy.