designing a better kit frame.

[Tristan Lall]

Given you mentioned fabricating it in the preseason, can I assume that this is something you'd like to see mass-produced and made available to teams through retail or KOP channels (e.g. as a future kit frame)? (If you're only planning to build them for your own team's consumption, then this advice may not apply.)

It's a neat idea, and it's got great potential for modularity. I think that you're looking at a lot of cost in fabricating it, relative to a kitbot.

The huge advantage of the last two kit frames was the ability to punch and bend them using sheet metal equipment. The raw material is relatively cheap, and provided you're sourcing them from a shop with significant investments in turret punches and brake presses, they're reasonably cheap to fabricate in mass production quantities too.

The problem with this design is the need for a lot of CNC setups to drill all four faces individually. (Well, you could do it manually, but that's obviously a ton of work; not a production solution unless you can get the cost of labour way down.) So for mass production on the scale of a kitbot, I would encourage you to think of other ways that a roughly equivalent part could be made. Maybe you could get away with C-channel made from punched and bent sheet metal (like the old kit frames, but a larger section). It wouldn't be difficult to rivet in a few smaller stiffening braces on the open side to carry the inner bearings, for example.

The universal mounting for the bearings is nice. But as you're CNCing them anyway, maybe you'd want to consider some more hole locations for intermediate settings. That way you could be a bit more flexible in using them as tensioners. Or if you want to get a little crazy, make them in two pieces: one sets the ground clearance for raised or lowered wheels, and the other one has some sort of pattern that allows you to rivet the wheels in place in a couple positions, e.g. on centre, or plus or minus 0.125 in to compensate for chain centre distance.

[Hawiian Cadder]

while this may not be massed produced, after our 2012 season, i will probably write a full paper, cad a sheet metal version, and submit it to Andy-Mark. you are correct that this frame has a TON of CnC work. however, the frame and gussets themselves only weigh 8.3 lbs, which of the amount of strength this frame would have, extremely light. the other advantage, is that even if we are unable to pre-fabricate the pieces, they can be fabricated durring the finalization of the design, and the CAD. which will still cut a 4-6 days off our build season.

while the 3*1.5 tube in this version dissalows more than 4, 6 at maximum different axle positions, the previous version used 4*2 tubing, and each wheel had 12 different positions. the 3*1.5 tube saves 4-5 lbs over the robot, but does make it a tiny bit less flexible. a sheet metal version could probably accommodate a larger number of axle positions.