Quote:
Originally Posted by JamesCH95
They look good. If you've got access to the CAD file would you mind switching the material to 4130 steel and making the wall thickness either 0.035 or 0.045? If that's easy to do I would be curious about the weight.
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Prototype Frame for 2011.
Aluminum (6061-T6) 6.1 Lbs
4130 .045" wall 9.3 Lbs
4130 .035" wall 6.7 lbs
I'd like to point out that a substantial amount of the "weight saved" was in changing the .125" wall 6061 for our siderails to the .045/.035, which would be very impractical for us to do without a redesign of our bearing block system (which would just be more work for a net gain in weight). It's convenient to have that .125 wall. For reference, this is generally our only use of .125 wall on the robot.
I'd also like to point out that for our particular team, switching to a welded 4130 frame would take a significantly longer time to machine and then weld, along with costing us more (in the short term, as we don't stock steel or any filler rod, etc...).
Also, I hear it mentioned all the time that welded reduces the temper of metal. This is true, I do not disagree one bit. I just want to throw a counterpoint out for the inexperienced people reading who might otherwise assume "Welding aluminum is AWFUL! it turns to butter!" (I know I did a few years ago). The weakened material will be in your welded joints obviously, and with a good frame design these won't be loaded to failure. We've never broken a weld in a driveframe before.
I encourage everyone reading who is re-evaluating their frames for steel, to also do so for aluminum; I'm not saying one is better than the other, but if you analyze the steel and fail to do the same effort into aluminum, you aren't really proving anything. For some teams one will be better, and for others, the other; do the math, evaluate your resources, and make a decision.