Re: Has any team or anybody made a 80% - 100% lexan bot?
 

Team 104 has used polycarbonate for a frame covering the last 3 years. We use 1/8" and 3/16" 6061-T6011 aluminum 1" angle for the frame joined with steel pop-rivets and backup washers. The polycarbonate is held on with 1" velcro. Mcmaster Carr sells velcro with a very strong contact adhesive. We have a sign shop make our decals to be applied on the inside. The inside of each panel is then painted. Our decals and paint can't scrape off. Note- make sure the paint is for lex an. Most paints do not stick. We have not experienced any frame damage or panel damage.
Polycarbonate is expensive. As was noted in another post, birch furniture grade plywood is very strong and light. To take it up another notch in rigidity and strength, Try laminating 5mm, 3/16 or 1/4" plywood with 1 or 2 layers of 4 oz. s2 fiberglass and epoxy. It's an excellent structural material and is fairly cheap. With our budget constraints this year we may have to use it.

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

Yes, but other aluminums don't fare as well. 5052 aluminum, for example, has ratios between 70 and 100. Other aluminums range from a ratio of 17 to a ratio of 237.

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

Yes, but the lexan motors kept on melting.... :ahh:

MrToast ;)

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

6061 is definitley the most commonly available (and probably one of the cheapest) types of aluminum used structurally. Most of the aluminum extrusion kits, and most of the tubing/angle/channel found on FIRST robots is 6061.

Additionally, Polycarbonate varies (you'd have to go to some other brand than Lexan) and glass filled PCs have ratios around about 80. I'm pretty sure glass filled PC is too hard and brittle for most framing use.

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

And just because the use of this by teams that have plenty of metal machining capabilities annoys me:

pipe type PVC ------ ratio 31

80% - 100% lexan bot?
 

Team 346 (Richmond) made one in 2001, I believe it was. There were a couple of pieces of aluminum angle connecting the Hyzod platform to the side panels. Each side was doubled up and contained a chain driving 3 wheels. It looked very much like one of those WWI tanks, as the front was intended to crawl over the 4x4 in the middle of the playing field. The polycarb was appx. 3/8" if I recall. I don't have pictures, but perhaps someone from 346 does. The frame held up well, although the bot was pretty light.

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

does anyone from 401 or any team know anything about this bot?

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

what exactly annoys you?

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

Heh. Perhaps that was a bad choice of words, but, in general, it is annoying when a simple design choice could have significantly improved the end product.

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

personally, i believe that using ENC (the grey PVC) is good design choice. its light, flexible, strong (enough), cheap, and above all, easy to work with.

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

empahses added

Re: Has any team or anybody made a 80% - 100% lexan bot? Yes, I have!
 

MY ROOKIE YEAR ROBOT!

Yes that is Sexy Lexy in her KSC glory. :D At Epcot we added a turtle shell to her chassis for additional protection and were attempting to install a hanging mechanism. Her gearboxes were lexan as well as the following years robot 3-bits (3-bits bad grrrr).

As many has stated it is expensive. Polycarbonate sheet is used as bulletproof glass. We got some donations from a local hurricane shutter manufacturer that year. However, an all lexan bot also sets you apart from the rest as some of us were remembered as the dudes with the clear robot. Before I digress any further, lexan is easy to work with basic machine tools you could get at home depot, loews or any equivalent respectable hardware store. That year if you looked at our pit, that's pretty much what we had at our shop. Belt sander, band saw, couple drill presses...... we've come along way.

When designing, you should also consider not only how will you manufacture it, ease of repair, but what materials. Obviously you don't want a large force extended out on let's say an arm that's just from what you made it out of not to mention whatever you intend to manipulate like this past year a ball.

Oh paint sticking... somehow we managed to get some neon green on lexy when we climbed on top of Swamp Thing somehow (ask Ares.. he was driving ;-)) almost 10 points but we were touching the ramp so only 5.

Thanks for the trip down amnesia lane. :ahh:

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

i look at it like this: i would much rather repair/replace an arm thats made from lengths of PVC tubing than an arm that is made from custom machined alum. at a competition. plus all the weight and/or money saved by using PVC can be put somewhere else, such as a drive train or electronic components.

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

another good part about pvc arms is that they wont dent or bend out of shape like some aluminum arms. And if you are worried about it shattering.. how easy is it to cut out the broken part, cut a new piece to size, and put it in with 2 couplers and some glue! woohoo go pvc!

Re: Has any team or anybody made a 80% - 100% lexan bot?
 

Tom beat me to it, but this fact was a driving force behind our decision to use PVC for a telescoping arm to reach the bar last year. We knew we'd be subject to punishment from teams cause we were reaching from the ground, and we knew there was a chance for the arm to get bent, so we chose PVC for it flexibility. We had our arm literally wrapped around a pole a couple of times, and it was fine. I saw a team at Lone Star have a metal arm wrapped around a pole, and it was ugly.

So, in summary, PVC definitely has its uses, and you just need to consider what you're designing for, like any other engineering choice.