Quote:
Originally posted by Chris Hibner
I forgot another thing: Lexan (and other plastics).
Wherever possible, substitute Lexan instead of aluminum. This is advisable only when the part you're substituting doesn't carry much load (if it carries a lot of load, you'll need to do some calculations to see if it will survive and not bend too much). For instance, all of our control system parts last year were mounted on an aluminum plate. We replaced the aluminum with Lexan and saved about 2 lb. The heat conduction properties of aluminum was nice, but the matches only last 2 minutes so it's not that necessary. You may need to reinforce the Lexan with a couple of thin aluminum strips to keep it from sagging too much, but overall, you can save a lot of weight.
Also, a lot of bearings can actually be replaced with delrin bushings. I would keep the bearings in your drive wheels, or other areas that cary an enormous amout of load, but delrin bushings are adequate for most spinning shafts that don't carry a lot of loading.
Just remember that you don't need to design your robot for infinite life. As long as it lasts a few months, it will be fine.
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And then if you find Lexan too dense for your weight budget, you might want to look into Luan Plywood.
Luan Plywood is 1/2 the density of Lexan.....sure, it isn't as strong, but there is alot of lexan use that is simply there to things like ball containment....not requiring so much for strength.
-Quentin
