80/20 frame Material Questions

[artdutra04]

Originally Posted by Nitroxextreme

Recently my team has been trying to design some frames, so that when build season comes around we will not be completely lost. I have been doing alot of research online and on ChiefDelphi, and I have come up with alot of different materials that we have been designing with. Some of these include square tube (both welded and bolted), bosch frame, plates and 80/20. Through these searches there have been some disagreements about advantages/disadvantages of each. I am now trying to get a detailed comparison list together, however I would like some input and personal experiences from other teams.

228 has used 80/20 frames since 2003; here are pictures of our 2005 and 2006 frames stripped down of almost everything else except the 80/20 and drivetrain. (Note that in the 2005 picture, the vertical 80/20 members at the 10 degree angle were actually used as a linear bearing for our elevator, which worked quite well.)

Most of my questions are specifically tailored towards 80/20...
What is weight comparison between 80/20 and similar size square tube?
What is thoughts on the different 80/20 methods of connecting pieces together (last year we used the old school 90degrees and they were heavy...I have heard good things about new anchor mounts)?
How has 80/20 worked for you in the past?
Whats thoughts on weld vs. bolt?

I think our team's mechanical engineer has already answered all of these questions.

If I can add anything, when considering whether to use a welded frame or a bolted 80/20, remember that welds are cannot be easily repaired at a competition if they fail. However, if you were to bolt everything together using 80/20 and the anchor mounts, even if you seriously bend a piece, you just loosen the anchor bolts, remove the piece, slide in a new one, and retighten the bolts. Done.

Your trade off for using bolts over welds is the increased weight (usually about 2 lbs). In the end you will have to decide if having an easily repairable and modifiable frame is more/less important for your needs than a permanently welded frame than saves about 2 pounds.

If I had to choose between a welded 1x1x0.125 aluminum box chassis or a 1010 80/20 (with anchor-mounts) chassis right now, I'd go with the 80/20. The reason? Modularity. The concept of a modular frame is amazing, especially when in week four of the build season if you're hit with a genius idea on how to improve x mechanism, or how to rearrange the mounting of y mechanism to improve its stabilty or rigidity.

Modularity of frames - whether they are Kitbot or 80/20 - can save a lot of headaches in the final stretch of the build season.