Chassis Material/Construction

This is my effort to make a meaningful thread.

I am interested in what all the teams use to make their chassis. We have always used Bosch extrusion and will be using it again next season. What do you use and what are the pros and cons of different materials?

All steel for us. We had a welded steel frame this year and it worked very well for us. It weighted a ton, and probably limited our design, but it was strong, cheap, and easy to work with. We have used aluminum channel and tubing before (2001 and our off-season OCCRA competition), but we like steel better, and we can get it fast and cheap locally.

/me <3 extruded aluminum

very useful when you design and build the chassis, then realize it sucks, and redesign it and rebuild it, then realize it sucks…

We don’t use any of that we, use 1/4 Aluminium plating with alot of holes in it. Makes for a very rugged robot.

Hmm…I think we use 1"x1.5" aluminum rectangular tubing. Not too sure on the dimensions. It’s sturdy. Uhh…and it’s sturdy.

The past couple years all we’ve used is different assortments of extrusion…This year we used more “aluminium tubing”(still extrusion?) because of weight.

:smiley:

Example:
http://www.chiefdelphi.com/forums/attachment.php?s=&postid=13472

We used 1/4" aluminum plate with 1/4" aluminum angle underneath for sturdiness. We also have a 1/4" aluminum angle V-cut in the front of our robot for handling goals. It’s sad though - it’s way too strong. Our engineer used it as a trampoline after he made it until his ankles hurt, but now we’ve cut too many holes in it for it to be used that way again.

Next year, bring on the extrusion and tubing! Let’s go for a frame, not a plate, woo!

*Originally posted by evulish *
**Hmm…I think we use 1"x1.5" aluminum rectangular tubing. Not too sure on the dimensions. It’s sturdy. Uhh…and it’s sturdy. **

Sounds about right, or at least something close. Don’t forget our steel anti-bumpers. Moe found out about them to well this year, there are still traces of them finding out about our anti-bumpers. :slight_smile: Ohh yeah… it’s sturdy!

We’ve used aluminum angle , extrusion, and angle iron.
We stoped using the aluminum angle because our welding teacher retired and we have no idea how to mig or tig weld(tried it once the results were not pretty) so we switched to angle iron which was much easier to weld, but weighed a ton. This year we used 80/20 extrusion which was nice and modular but was heavy also.
So out of my expieriance the best framing material is some sort of aluminum structural material like box or angle that you weld together because you just can’t get a stronger lighter frame that actually allows you to put other mechanisms for the other part of the game on the robot.

This past year, we used 30mm x 30mm Boasch aluminum extrusion. It’s sturdy, it connects well and we get a discount on it! :wink:

  • Katie

We always go by are moto ( Wood is good , Steal is real , and plastics fantastic ) just to share a little humor with you guy !:smiley:

We used Bosch, because the team welder graduated last year.

It’s great stuff to use, you can build a bot in no time, and disassemble it easily… but it adds unneeded weight. You could probabaly use 2 bars of aluminum tube for every 1 Bosch, and still have it weigh less and be just as strong.

But, hey, it worked great for us, so I’m not complaining.

Heh, it’d be sweet if someone built their bot outta polycarb. That’d be rather fragile tho. Just get some nice 3/4" thick polycarb :stuck_out_tongue:

The bosch aluminum extrusions are not much heavier than the same size square tube with an average wall thickness. The extrusions are great for changing design, quickly adding mechanisms, and moving pieces without drilling. It’s a snap to build and makes the whole project more modular. It is incredibly strong too. Also, its only a couple of bucks more than sq. tube.

The only downside is the cost of hardware. Those little brass alloy T-nuts are like 50 cents apiece. There’s also the wierd metric hardware that’s a little more money and harder to get then American hardware. The joiner plates are just a rip off so we make our own.

For those of you who voted wood, can we see some pics?

Heh, it’d be sweet if someone built their bot outta polycarb. That’d be rather fragile tho. Just get some nice 3/4" thick polycarb :stuck_out_tongue:

Somebody did. In 2001 (I think Adam knows this story better than I) they only used Lexan as a building material. They made 1/4" lexan angle, lexan sidepanels, and everything like that. No structural steel or aluminum at all.

It was pretty cool looking :slight_smile:

EDIT:

Forgot to mention who it was! It was team 401. We were next to them in the pits at VCU, so I remember them lifting up lexan parts of their robot I could see through while we worked.

*Originally posted by Gui Cavalcanti *
**

Somebody did. In 2001 (I think Adam knows this story better than I) they only used Lexan as a building material. They made 1/4" lexan angle, lexan sidepanels, and everything like that. No structural steel or aluminum at all.

It was pretty cool looking :slight_smile: **

Yeah, but in 2001, you could get away with that. The structural concerns were not as great when you knew you weren’t going to be in contact with opposing bots.

We noticed some NASA teams that pre-made connectors (like tinker toy ends) that hold tubing at different angles in the off season. THe keys here is build your ‘proto-type’ out of BOSCH then make the final out of tube by quickly rebuilding straight tube sections fitted into the pre-made connectors and giving it a little weld, which is much faster than making the custom ends on each piece when time is an issue. We will probably do this for 2003.

Bosch is great stuff, it just weighs alot, we did find we could ‘remove’ some excess material from sides we weren’t attaching to for weight savings and it still was pretty strong stuff.
30x30mm

We’ve been using polycarbonate for several years now - I don’t think anyone would accuse us of being fragile. This year our front frame was aluminum tubing and center pan was aluminum sheet, but most of the rest of the chassis (including the gearbox housings) were Lexan. It’s easy to machine and assemble - it taps very easily for individual brackets and we use self tapping drywall screws for general assembly. A couple lessons learned - grease the screws and don’t use locktite - it will shatter the laminate when it heats and cures. A key thing to remember in battle is that low spring rate materials will absorb impact energy better than stiff materials and lexan does a great job.

wheelman already said what we use

Badjokeguy

God Bless 80-20! SEE IT HERE! We usually go for the 1"x1" extruded 80-20 with 1/4 inch aluminum plate for the body. And also some 2"X 2" as well.

see example here and here

Yeah, we got some free samples of that stuff.

Could you explain a little about the “castors and one wheel on each side of your robot thing” I see in the picture?