Re: Best frame building material
 

A good frame material I've heard of is carbon fiber board. You know.. the stuff motherboards are made out of. I'm guessing that if you make a basic chassis out of steel angle irons, and bolt on sheets of carbon fiber, it'll take a lot more damage than if you have polycarb side panels.

A related question:

I've seen how they make some airplanes, they get a big mold and use a special machine to lay carbon fiber all over it, making a shell. I've also heard they use this method for race cars. Of course I doubt many FIRST teams have access to NASCAR shops, but does anyone know how carbon fiber laying works? It would be cool to see a molded carbon fiber frame some day.

Re: Best frame building material
 

Team 598 used a carbon fiber shell with Kevlar for support. That is really smart because both materials are very strong and very light. We use 60601 T6 aluminum but thats only becuase we do a lot of welding onto the frame and its the best application we have found. Just the right strenght and its light enough.

Re: Best frame building material
 

Not quite. At least not in our case. FRP = fiberglass reinforced polyester.

As RBrandy pointed out, we used the square profile tubing for our robot and modified unistrut to provide connection points. There are certainly other ways to connect FRP components. We're looking at corner/T plates for this coming season. In a few instances we used nylon bolts and nuts to hold non-critical components together. They fared VERY well and are extremely light. We all know how quickly hardware can add weight to our robots!

As for availability, we purchased our FRP through Ryerson, a national distributor. McMaster Carr also carries FRP and actually has a wide assortment of shapes including sheets, u-channels, angles, solid and hollow rods, and square tubing. Prices are reasonable with square tubing going for about $3.50/foot. Check it out at McMaster-Carr. It is drillable, machinable, paintable, and extremely easy to work with!

A picture of our application of FRP can be seen here.

Sorry for the delay in responding to all the inquiries and good luck!

Sean

Re: Best frame building material
 

(In response to welding)

The problem with NOT welding is weight. What I would suggest a team do (if it has some money) is to weld spare parts that are likely to get broken. For example, an arm is easy to break, and so is the frame. Weld spares of those. Additionally do NOT weld the entire robot. Weld PARTS. Weld a bottom frame and separately weld the top frame, and bolt those together. 4-8 bolts = better than 40 - 80 bolts.

Re: Best frame building material
 

One thing about composites like carbon fiber and the like which is really important.Don't not breathe the dust from carbon fiber. It causes lung cancer. The splinters are nasty also. They dont become infected like wood splinters.

Re: Best frame building material
 

Fiberglass splinters are freakin evil. Between laying fiberglass insulation, and creating a fiberglass shell for The Sandhill Challenge racer we built in 2001, I've come to hate it.

Re: Best frame building material
 

Word up for the Baltic Birch ply wood. Our team (195) has been using 9 ply for the last 4 years and its worked pretty well for us. What we usually do is build the box and paint it and then screw plates of 1/8 inch lexan around the outside as protection against dents, alot of times we will also reinforce the front and back with some 1/8 inch angle aluminum because in some extreme cases the frame has cracked on us. The aluminum angles seems to aliviate this. Our last bit of "armor" is 4 upright pieces of 3/16 inchangle aluminum at the corners to guard against spiliting. This has proven to be very structurally sound and also presents a good base for mounting things; blind nuts for important things, machine screws threaded into wood for relays, speed controls, etc.

P.S. Shameless plug for Gorilla Glue. :D Works awesome on our frame.

Re: Best frame building material
 

Our team used extruded 8020. It's really light and easy to work with

Re: Best frame building material
 

!?!?!?!?!
I will agree with the easy to use, it is an industrial erector set :p .
BUT as for light weight... 80-20 is heavy stuff. That is were the the compromise comes in for a lot of teams, go with it and its easiness and sacrifice on the scales or build other lighter more challenging implements.

edit/
I think I should add that I do realize this is a year old thread, but still relavent. :)

Re: Best frame building material
 

I wise engineer once told me two things
1. There is no Best material, there are Right Materials.
2. Use the right application for whatever your material is.

Ok so time for what i think of Chassis materials, from the extensive research i've done at competition I have found that combinations are the best way to go, making a frame all out of one material is inefficent. Also Extruded Aluminum is a proven FIRST chassis material.

Re: Best frame building material
 

Thats not entirely true...

Our entire frame was built out of extruded, given it was was only 1/16th" wall 1x1, it only weighed about 14lbs! Thats not very much for how much frame we had!

Go here and click on 2005 Build to see some naked pics of the bot! :rolleyes:

Re: Best frame building material
 

so that held up for you guys pretty good? I saw a couple teams use 1/8" on the outside and 1/16" on the inside and other supports. But it all matters on how you apply it.

Re: Best frame building material
 

In the past few years, I believe that my team has gone over kill on frames. We used 2x4 extruded in an H shape, 80x20, and the kit frame this year. All of thoes were overkill and never took a single dent. So this summer we are going to try a few frames. What experience do you guys have with the strengh of 1.5" angle alluminium?

Re: Best frame building material
 

We used 1.5" aluminum angle for the front and back of our robot for the
past two years. Last year it was fine because "violent" robot interaction
occured up on the platform and there was no room to build any speed.
This year we got the front of our robot bashed in during the quarter finals.
I doubt we will be using 1/5" aluminum angle in this way again.

Re: Best frame building material
 

[quote=cdr1122334455]I wise engineer once told me two things
1. There is no Best material, there are Right Materials.
2. Use the right application for whatever your material is.
QUOTE]

Very good - and true. Each application is unique.

862 has used plate aluminum, 80/20, welded aluminum tube, and "L" channel in various years. "L" channel (of various sizes) has worked the best for OUR team on the frame. But that's because we don't weld (for many reasons, even though we have MIG, TIG, and Arc welding equipment), we have a tendency to over tighten without spacer blocks (crushing box channel), and we don't use/have CNC Mills or Waterjet cutting (otherwise plate would be nice).

For us, material selection is based mostly on fabrication technique. Look around, see what other teams with similar resources use, and try it out over the summer.