Modular Building Systems

[Kevin Leonard]

I would highly recommend VexPro VersaTubing. 5254 is a young team with extremely limited machining resources in Upstate New York.
This past season, their robot was almost entirely made from cut-to-length sections of VersaFrame, and it made finals at two events, seeded first at one of them, and was a first round pick in their division at championships.
They did so by building simply and within their resources.

[philso]

I feel it is more important that your team learn to design a robot than it is to draw a robot in CAD. Designing the robot requires thinking about what it has to do, what materials it can be built from and how it can be manufactured.. This thinking is what determines the quality of a design, not how the design was implemented. Once one has worked out a good design, it can be implemented in CAD or on the back of an envelope. If your team is not sufficiently fast at CAD, then the designers will spend all their time "putting parts on the screen" instead of thinking about the design. Your team may get the most value by using CAD as a tool to work out things like geometries (how long does the Canburglar need to be and where does the pivot point need to be).

Last year, we had one student who is a very proficient CAD operator who drew up all kinds of mechanisms that ultimately did not work, could not be built or did not have adequate strength (catapult). He also was of the opinion that "CAD is perfect". We have professional designers at work who make the same sort of mistakes.

This year, we threw out the custom sheet metal trays for holding our electronics and control system because the CAD of the robot was missing the parts needed to retain the sprockets on the shafts for the drive wheels. Adding those parts meant the shafts protruded too much into the electronics tray and would hit the electronics components. The design was extremely tight and the close proximity of the parts on the electronics tray and the drive wheel assembly meant that neither were serviceable and assembly could only happen in a particular sequence.

If you are using a sponsor to make parts for you, make sure they will deliver the parts in the timeframe you need. I recall watching one Houston area team un-bag their robot and frantically finish the assembly process because their sponsor was late and delivered the parts the day before bag and tag.

[Scott Kozutsky]

I'd go as much versaframe as possible and use the 1:1 drawing on paper-glue-drill press method of making any gussets that need to be different and accurate.

I'd also highly recommend getting either a scroll saw or a bandsaw to help make anything more custom/ irregular.

Try to CAD the robot before you build it to make sure that everything lines up before you build it (IMO, CAD is pointless unless you use it to design your robot. If you build before you CAD, there's no reason to CAD because it's not influencing anything).

I'd avoid tetrix because of the cost if possible. Same reason I'd use wood (it really does work well for most things).

The best robots in FIRST are rarely the ones that are crazy complex, try to make a simple robot within your means.

[asid61]

Even if you think you can't handle it, get a mill and learn how to use it. They are invaluable for making things in precise locations; you could make your own versatubing if you get anything with more than 12" of table movement. There are plenty of videos online about operating one.