What suggestions are there for materials to have on hand for prototyping the first week of build season? This is my first year involved with a team that doesn’t have a large stock pile of materials and parts from previous seasons.
Some things that I’ve come up with:
Plywood and lexan
Aluminum sheet, angle, and box tubing
Nuts and bolts of various sizes
80/20 (Good for structural standoffs)
Surgical Tubing
Wheels of various sizes and hubs
Motors from 2015
What else are we missing? Anything on this list that you don’t think we really need?
Do yourself a favor and only use only one or two hardware sizes. We historically have used #10-32 and 1/4"-20 hardware (though only rarely the latter, it really is overkill)
If by various sizes you mean lengths, then yeah that is fine.
We mostly commonly use 1.5" for bolting panels to 1" extrusion, 2.5" for bolting two extrusions together, and .75" for bolting two or three panels together
Help me love this tool, I’ve had nothing but bad experiences. How do you mark the bit so roboteers drill only to that size hole? In a drill press this should be easier assuming that the roboteer uses the drill press and understands how to correctly set the stop. But roboteers traditionally love the battery hand drill.
I was part of a team purge that got rid of all the Phillips, Robertson, Torx, straight blade, etc heads, wood, self tapping, etc. and replaced them with cap head bolts (and added some extra sets of T-handles) Restocked with a few diameters and multiple lengths. Seemed to work out well, only down side was when doing prototyping with wood parts needing to drill holes for fasteners. But hours saved not looking for matching screws or needing to use a Phillips on one screw and straight tip on the screw next to it was huge.
Don’t forget the prized prototyping material; the pizza box + duct tape.
We’ve used the cardboard lid of a pizza box to initially prototype a variety of items (both on the robot and for the playing field) because they’re handy (accessible) and cheap (re-using)!
Good luck!
Standardizing on heads sounds like a great idea. Related to this is stocking multiples of key sizes of tools and not just buying a gigantic “one of everything” tool set. Sure you’ve got one of every possible socket or wrench in the giant set but three of your students are looking to use the same 7/16 socket to work with those standardized sizes and you’ve only got one…
2x4’s and 2x3’s should be your go to material for prototyping. A lot of the best teams use them for prototyping. Look at 254 in 2014. Also, vex hex shaft and thunderhex is good because it can drive most wheels for prototyping and a minor modification makes them able to be driven with a drill. Watch the recent game sense series on prototyping. Other good materials are the igus products. Super quick pivots and mock ups of arms can be made using igus.
Watch some of the 973 RAMP videos on designing with sketches in CAD. One thing we’ve been known to do is print off full-scale drawing templates to trace for our prototypes and actual parts. Works great and gives the students an additional visual aid in addition to using traditional measuring tools.
The trick is to build your prototype to a high enough quality that will allow you to actually learn from it. A flimsy prototype that falls apart on its first use isn’t a good prototype. Wood is a great material because you can keep drilling and adjusting things on the fly too.
For rookies, I’d highly recommend getting your AndyMark drive base assembled ASAP (have a few people start building it week 1, heck even day 1) and then attach your prototypes ontop of that frame to give you a more real-world test. Most teams use previous season drive base platforms but you most likely won’t have that option.
If all you have for a drive base is that one KoP chassis, I recommend waiting until you have your overall robot design done, at least to the extent of knowing your horizontal dimensions, drive type, gearing/speed, and any interruptions that you will need in the frame (e.g. for game piece pick up). We did essentially as Ryan suggested above our first year (Rebound Rumble, a basketball-based game), and seriously compromised our chassis’ integrity when we added a gap to pick up balls.
It’s probably obvious to you as you’ve done this before, but for rookie teams especially: Decide before you start building something whether it is a prototype or will be the competition part (subject to later modification, of course). If it’s going to be a competition part, you’ll want to do a more careful material selection and construction than if it is just a prototype to provide dimensions and such for the real mechanism. With a prototype, you can stretch dimensions and weight that you know you will have to tuck in when you build for real.
