4 and 5 Axis CNC in FIRST

I’m curious to see if and how teams are making use of technology that we don’t have. Are you using 4th and 5th axis CNC milling & routing tools on your team? If so, what did you use them for?

Bonus points for Photos!

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For 99% of teams 5th axis and 4th axis are not very necessary. The most I see most teams doing is flipping over parts to machine both sides, but that can still be done on a normal 3 axis a lot easier. That said…

My team (3200) has access to a beautiful DMG Mori DMU95 Monoblock 5 axis mill through one of our sponsors. We have never made a part on it that needed the 5 axis capabilities, but it can make things a lot easier when we can reduce the number of machining operations by having the machine reorient the part for us. We custom make a ton of COTS parts (bearing blocks, wheel hubs, etc) to save money. We can make a dozen versablocks for the same price as buying one set from VEX. We have also made gearboxes, mechanism components and other random robot parts from billet pieces before, but seriously you don’t need to do that.

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We have a 4th axis that we leave set up in our machine but truth be told, it sees pretty limited use. 2019 we did some actual production on it for our robot, lightweighting some drive hubs. We did a run of about a dozen parts at about a 25 minute per piece cycle time.

For 5 axis we have a little PocketNC just as an educational tool. Again, haven’t done much on it yet.

The bottom line is, it takes a pretty good investment of time to get setup with all this stuff, and there’s only so many hours in the day/week/year. In the hustle bustle of FRC season, it’s rare that sitting down to design, program, and set up a 4th axis part provides any distinct advantage in the number of points your robot can score in a match. We like having the capability to do neat things, but rarely is it advantageous from a competitive standpoint. For us it’s more of a learning tool for students to experience what’s out there in terms of industrial manufacturing capabilities.

Now, I will say that there have been a number of times that students and I have encountered parts where we’ve said “this is why we need a live tooled Y axis lathe.” That would be pretty sweet, but is way above and beyond pretty much any FRC team. Someday…

I wish some of the value in custom machining would be brought back into FIRST. A lot of the value in custom work was destroyed with the proliferation of high quality COTS parts. But, that is not a debate for this thread, so I’ll leave my comments at that.

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I think @CalkinsGarrett has a start on how that can be in the modern age.

I don’t see things going all the way back to those gorgeous mid-2000s 233 machines, but a team that develops the right relationships and access can save a bunch of cash and avoid supplier stock-outs even if they aren’t as wildly customized in their designs.

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One of our (1690) mentors has access to a 5 axis CNC mill. Our most notable use of this technology is our swerve drive wheel/bevel gear combo and the small brass bevel gear. Most of the time he uses the 5th and 4th axis to make machining complex parts (such as our wheel forks) easier, without having to reorient them.

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Why do you mill out the hex instead of broaching it?

My guess would be that it takes less time (maybe not less machining time but the lead time to have them at hand) to mill out the hex on the CNC mill than broaching 2+ robots worth of brass gears. Also, milling the hex gives 1690 more control over its tolerance and could possibly help eliminate backlash (although for this purpose I don’t think it’s a major concern).

That’s what I thought at first, but based on how small the relief is I’d imagine you get some decent amount of tool deflection. Plus, a broach is generally ground to tolerance so it should have some tight tolerances. Unless of course, the time savings as you said.

We don’t have a 1/2" hex broach on hand, plus the mentor responsible for it said he preferred it to be milled out :man_shrugging:

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That’s interesting; How well does the hex fit?

Do you have any photos from the setup on these? Home Making Bevel gears is a really cool application.

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We have access to 5-axis mills through our sponsor Elbit, a defense contractor. We try to make as much of the robot as possible in house on our CNC router to speed up manufacturing time (and make replacing parts easier when we inevitably find things need to be changed), but every year we end up sending some of the more complicated, higher-tolerance, weird material, or high volume parts to outsourcing. We’ve never purposefully used their 5-axis capabilities, but we know in the back of our minds that it’s available if we need it.

Notice I said “never purposefully used”. That’s because in 2019 one of the parts we sent them to make was designed by one of our newer students and the model was sent out without being thoroughly checked. When we get the parts back from our sponsor, they mentioned that it was funny to see we finally used their 5-axis mill. Turns out the part was a normal 3-axis billet part, but to make it look nice the student rounded the sides of the billet. So these relatively simple parts that should have taken 10-15 minutes to machine accidentally became parts that took an hour or more each. Notice how the sides of the part are slightly rounded. That’s the 5-axis at work!

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That’s awesome. I love that they were happy to have fun with the part. What was it used for?

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A nice, tight fit, just like we wanted

Unfortunately no, the facility in which they were made does not allow any photography

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They’re amazing supporters of ours, and they love it when they get to help us design and build the robot. We’re very glad to have them as sponsors.

That part connected the profile that held our climber wheels to the lead screws that drove them into the ground. Our climber that year never really worked right, and we only climbed to HAB 3 once in an official match. The profile ended up getting absolutely destroyed in a playoff match before it got replaced between competitions (for another system that also didn’t really work)

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Multi axis machining is not a super competitive advantage in FIRST. You can make cool stuff, but cool does not win matches. The time and cost investment does not make sense for the FIRST Competition. With that said, FIRST is a side project in my career as an educator. My primary focus is to produce career and college ready students…so we machine lots of parts with “cool factor”. Also, it is worth mentioning that students CAD/CAM and CNC all their own parts. We do not sublet parts or have mentors come and save the day. It takes about two years of training to get a student to run five axis mill without direct supervision. A big investment in time, but these kids get careers and that is what FIRST is all about.

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The first pic is a vector wheel. Props to team 125 for posting the cad.

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Just out of curiosity - did you actually use these wheels on the robot? Why did you make them out of Aluminum rather than some kind of plastic? Also, could they have been made in one piece with two setups for the roller pin holes?

We did use the wheels on our intake. Plastic works fine and we made some 3d printed wheels for testing. The aluminum wheels was a task that a senior did in week five after the robot was functional, so no important time was lost. I am waiting to see how the plastic wheels do outside frame perimeter in heavy defense. Plastic vector wheels are still new to FRC.

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The metal VIW would be a great core for a casting mold. You would have much nicer surface finishes than using a 3D printed part as your blank