Chassis Connections

[M.Wong]

A very easy method for creating a chassis would be to use 1"x1"x1/16" aluminum tubing with Brunner Connectors. In order to secure the pieces together, we use 1/8" thick aluminum gussets with sheet metal screws.

This method allows easy modification of your chassis without having unweld or cut away pieces.

[Clem1640]

Last two years we have used welded frames. Mostly 6061 Al MIG welded.

Before that, we used bolts.

Reasons for the shift to welding:
1) Weight! No connecting pieces. Reduced nuts & bolts.
2) Strength - a well-welded frame is nearly as strong as the native aluminum.
3) Durability & Maintenance - Bolts work loose. Our welds no longer break. There's a learning curve here.
4) Design - As head of the Design Team, I am well aware that it is easier and faster to design a welded frame than a bolted frame. Especially if you are paying attention to detail (and the devil always hides in the detail).

The other benefit is that frequent welding makes us better welders, and yields welds less likely to fail. It also becomes easy and fast. We are now able to weld on the fly.

Downside is that when a critical weld fails, you need to work out a field fix. This can be easy. This can be damned near impossible.

Still, for us, the benefits of welding (applied to the right places) overcomes the costs and dangers.

[JamesCH95]

I would like to add that 4130, when welded with the proper filler material, can be stronger after it is welded. I developed and got AWS certified in a pulsed-TIG process for welding 4130 tube frames. My process used ER-80S-B2 wire, the 80 standing for "80ksi yield strength" in the filler, where annealed 4130 is about 75ksi (I like english units for welding as designations start to make sense: A36 = minimum yield strength of 36ksi, etc). The resulting welded material was stronger than the base material, but still ductile enough to be run through a tube-bender (and anyone who has done it can tell you that bending 4130 is very difficult).

Clem1640: watch out, your 6061T6 is becoming 6061T0 around the welded areas!

[Siri]

Originally Posted by JamesCH95

Clem1604[sic]: watch out, your 6061T6 is becoming 6061T0 around the welded areas!

That it is. Luckily, we're [same team] pretty good about design strength & redundant supports. We've yet to fail a critical weld in 2 years* (though we do bow some). Still, I look forward to the the day we win the lottery and can correctly age back to a better temper. ...Then again, I look forward to that winning ticket for other reasons too. Like TIG welding!


*knock on...wood.

[rcmolloy]

For the past 3 years, our team has had our chassis fabricated out of 3/16" aluminum. The sides are bent at 90 degree angles for us to mount our bearings for the gearboxes. Also, this year we had two machined pieces of aluminum as well as custom brackets for our piston system. These have been helpful for more low to the ground games and our strategies. Here is a picture of the actual chassis alone without electrical wiring and all pnuematic tubing.



I know arial views don't simply do justice but I believe you can get the picture from here. If anything, I will take a picture of the chassis we have hanging around at the school from 2 years ago. Let me know!