Ever since we've started teaching the students to TIG weld, we've come to appreciate the beauty of thin walled aluminum tubing. It's hard to get much better than that for most structural applications when you can just stick it together with the TIG.
But that doesn't mean we don't have a passion for trying out "alternatives". Go to
www.trobotics.ca and click on "robots" for a walk thought of some of our machines.
2004 - Plywood main chassis, fibreglass with urethane foam core on the top layer.
2005 - Arm 100% plywood, could support two judges jumping on it at the same time in a 3 point loading test (we brought a spare for the demo) and was lighter than most other arms. Main parts of the frame (sides and back) are urethane foam core fibreglass again. The materials helped us win Xerox Creativity in Portland.
2006 - Our first try with thin walled aluminum tubing, but note the use of plywood (baltic birch) for the turret and ball intake mechanism, as well as the nicely turned main drive wheel on the ball lift belt made of phillipine mahogany. Coroplast secured with velcro made for nice light side panels.
2007 - Wooden lift (using IGUS track in a rabbet) of baltic birch ply, tube gripper and mount of baltic birch.
2008 - Carbon fibre hockey stick ball lifters... the CF sticks replaced some plastic floor hockey sticks that didn't like hitting the field wall at full speed. The sticks were donated as they were from broken sticks sitting in the Portland Winterhawks' trash bin (we ran out of spare wooden and plastic sticks on practice day in Portland). The love affair with baltic birch ply continues with the main robot body. GM Industrial Design winner in Seattle.
In short, it is fun to use something other than aluminum, and -- when chosen for good engineering reasons -- can attract positive attention from the judges.
Jason