pic: Offseason Shooter CAD Project

[Sperkowsky]

Originally Posted by Chris is me

Snip

First of all thanks. I will say getting better at CAD is something I have put off for about a year. I always saw CAD as something necessary to gain measurements and translate ideas to other people but until recently I did not realize its a great tool to come up with designs as well.

With the off-season robot I have been trying to make it as cheap as possible. I reused our wheels, belts, hubs, and motors. I also used some of the spare material we have leftover in our shop. If we were to build the robot we could probably do it for under $500. But, there are priorities like funding for a second regional, funding for both a normal robot and possibly a practice robot along with hopefully funding for our first champs trip.

We have a water jet sponsor and cnc mill sponsor. The cnc mill sponsor is new so currently I designed everything as if it was going to be water jet cut. There are 0.1 fillets but that is not big enough for milling. The cnc mill sponsor is kind of unique in that its not a normal service. They use large HAAS machines but restrict the size of parts due to the way they operate. Being we are sponsored by them and not a normal customer I am not sure whether we could get an exception. That's something we can hopefully work out. We also just bought a Shapeoko 3 XL so we possibly could cut the plates with that although we do not plan to do that as its really not optimal.

I was talking to some people about adding large AM Steel gears and I think I will proceed in doing it. It would also be cool to test the difference in shot arc, speed, and distance with and without the added weight.

I agree with all these comments about ball retention I am seriously doubting the compression is good enough. Currently I think I am going to add arced lexan strips on both sides. We have a lot of tooling to help with that sort of thing like specialized heaters and brakes so it is a nice and easy job. Plus its a good learning experience for incoming freshman. In terms of wasting material I agree. But, I do like that assembly a lot so what I did was change the material to Lexan. Its easy enough to cut on our router and we have a ton of it.

Lastly thanks for the last thing. I was not sure whether there was enough material left over. The L bracket idea works good for us currently. Quick question. We are currently trying to get a welding sponsor. Would welding these work well?

Thanks for the help.

[Cothron Theiss]

Originally Posted by Sperkowsky

The L bracket idea works good for us currently. Quick question. We are currently trying to get a welding sponsor. Would welding these work well?

I'll go ahead and throw in my two cents about how to attach those side plates. I would not weld those on, for a couple of reasons.
First off, what material are these plates being made out of? My first guess would be 6061-T6 aluminum, but it could be several different alloys depending on your water-jet sponsor's resources (and generosity) and your needs. Depending on which material you choose, you may not be able to weld it whatsoever. Secondly, you'd probably have to remove all of the pocketing around the area you'd want to weld just to ensure there is no weakening of the plate itself due to the weld. Also, having to send off this assembly to another sponsor would most likely increase your turn-around time quite a bit, for only a few small welds.

My suggestion would be to cut out these side plates and then bend them into a U-bracket of sorts (you mentioned you had brakes). Again, you have to consider your material considerations for the plates you're bending, but that constraint only applies to the side plates themselves. Also, if you design the side plates so they mount using the holes you're already using for the standoffs, you can get away with only changing the design of the side plates.

However, if you go down this path, you have to have pretty accurate bends. If you incorporate some guiding grooves into the design of the side plates and you have members who are pretty careful, you can get away with a hand brake, but it is another thing to consider.