[Travis Schuh]

Originally Posted by cxcad

Looking through 971's photo album (I'm a super fan, lol), I saw that they have made their own CNC router. And some questions popped up.

• Why would a team do such a thing when so many CNC routers are out there? Cost of a custom one?
• What type of resources like books, manuals, designs were used to build such a router? I know there's tons of resources on building ones that can route through wood but very few on aluminum specific ones
• How much skill does it take to design such a router? It would be cool to have the students work on it as an off season project.

....Any plans to share the design (wishful thinking)....

We decided to build a router after the 2014 competition season, and got it cutting parts this past August. We made the 3rd robot (the one we used at Chezy Champs) almost entirely on the router, and we were really pleased with the performance.

• When we started looking at routers, we decided pretty early on that the commercial routers on the market that we found within our budget all had design compromises that we were not a fan of. Our goal was to be able to have enough rigidity and precision to be able to cut bearing press fits in aluminum. This lead us to build our own using Chinese ball screws and linear bearings. This took a huge amount of time (I would estimate a 971 season or so of work), but I think the time invested payed off.
• We did some research of what other routers (and gantry mills) out there looked like, combined with a lot of design iterations and FEA. We analysed a simplified model of multiple router architectures using FEA to characterize what their deflections were. We went through a few different ideas before we found one we liked. Then we spent a bit of time working on getting the stiffens of that design up. We also got a lot of feedback from 973 and 1323 about their router experiences, including 973's custom build.
• Designing a router has a lot of parallels to designing a FRC bot (at least in our experience), and we were able to leverage a lot of this experience for designing the router. We did spent a lot of time on the design and fabrication of the router. We started meeting every weekend early in the 2014 summer, and continued right up until kickoff. Fabrication started around September and assembly around the end of November. We unfortunately barely ran out of time to get it running for the season, but were able to get it up during the 2015 summer in time to make the 3rd robot. The design and fabrication effort was done mostly by mentors because of the nature of the scope and because the kids had their own off season projects that they were working on that fit better with our team learning objectives. I hesitate to recommend designing and making the router we did as an off-season project for the kids, but I don't know anything about your team.