We have a CNC router, CNC mill, and CNC lathe, along with a manual mill and two manual lathes with DROs. If I could only have one CNC machine it would be the router, no questions asked.
We rarely use the CNC mill (only when the router is backed up and we have small parts we can make in parallel) and really never use the CNC lathe. If we need to make a truly 3D part (not 2.5D that can be made on the router), it pretty much exclusively gets made on the manual mill. It’s a lot easier to make the few 3D parts by hand each season rather than deal with setting up the CAM for the CNC mill. We also make a ton of use of our manual lathes for making shafts and spacers. But again, it takes less time to make each part by hand than it would to make the CAM for the part and then let the machine run. For what we need, a mill/lathe with a DRO is accurate enough. If it needs higher accuracy it goes on the CNC router or gets send out to a sponsor’s machine shop.
I know I got asked some questions while we were setting up our Velox and over a few runs that could probably have been answered had the folks setting up the CNC known the Bridgeport moderately well. Including a “how to use the collet” question, feed/speed, part-holding…
I sometimes think it’s “machinist mindset”–you have to think about how you’re working the part, and how to set it up. If you don’t have that, you’re going to have to learn it, and it’s IMO somewhat easier to learn on a manual mill (any size) than on a CNC (any type). But once you have it and know it, it’s a matter of applying it to whatever machine you’re working on. You CAN get it on a CNC… but it might be expensive if someone who doesn’t have it isn’t mentored by someone who does have it.
We basically lost all our students with machining experience from 2018 to 2019, the same year we acquired an Omio. While we did have some of the “level zero” knowledge that needed to be acquired… how a collet works isn’t too hard to pick up.
While I’d certainly agree it’s possible to make expensive mistakes, the worst we’ve had was students breaking bits. The most important piece of “level zero” information for a CNC is where the stop button is, and where the e-stop button is. Knowing those, most things can be recovered and most damage can be avoided.
Maybe we’ve just been lucky, but as someone who was basically re-learning all my machining knowledge along the way (the last part I milled before we got the Omio was in… 2013? 2012?) I don’t think a lot of that was hard to pick up. The biggest thing I’ve found (which applies to learning anything alongside students) is having a good attitude about learning and mistakes. If you approach it as a big hard thing, that’s what comes across and affects their attitude. Maybe it’s less a matter of a “machinist mindset” and more a developed intuition for risk. I definitely don’t have a machinist’s mindset.
If a team can afford to buy a new/used waterjet, and afford to maintain it, its #1 on my list of what I would recommend to a team in FRC.
The amount of time and effort we have saved by having one, is worth every penny to me. We put all of our new 8th or 9th grade 1st year students on that machine, and usually have 1-2 veteran students overseeing it.
Time is money, especially if youre from Hawaii and the build period time is significantly shorter than the average team. We also dont have any sponsors/shops we can just go to, to get things cut if we didnt own one.
Several Hawaii teams come to us now to have parts cut for them. And we are happy to do so.
Something I haven’t seen mentioned here: organizational tools. After the CNC router, bandsaw, and 3d printers, toolboxes and part storage will be the most bang for your buck hands down. You will save time and money when you invest in lots of organizers.
Aa a side note, a really big Doall or Grob bandsaw is much better than a smaller rolling bandsaw for cutting metal.
Standard reminder that something that’s been alive since the Cold War is probably going to continue to outlive you. Stalk your local Craigslist for any large machine tools as well as awesome storage solutions that don’t use absolutely garbage sliding rails and paper thin stamped sheet metal can you tell I’ve been hurt by this before?
3D Printer - Largely because competent ones can be had for $200 and serve as an intro to digital fabrication and design, it’s a low cost/risk way to teach students.
CNC Router - very useful for putting tubes together which, given the current vendor climate allows for a lot of flexibility.
Lathe - Again, given vendor climate, this is less required than it was in years past. But for cases when you need to make parts round this really is the best option. Most teams can probably get away with a 7x14 lathe though which can be had for relatively cheaply.
I don’t even see a use for a CNC Milll for most problems in FRC. Sure if you have it they are handy, if you don’t it’s something that can be designed around.
Do you have a recommendation?
I’ve tried the monoprice mini delta and can’t get the bed adhesion working.
Right now I don’t recommend anything cheaper than (prusa mk3 / matterhackers pulse) because I want tools I can use, not more side projects…
This should probably be in another thread…
Ender 3 is good for that price range. My MP Mini Delta never had adhesion issues but it was never super accurate (I never really bothered to tune it). Worked well for spacers and small odds and ends though.
The Ender 3 is my go to recommendation. Does require tinkering at first but generally once it’s dialed in it’s pretty reliable and there’s enough resources to help out there because it’s massively popular.
I’ve heard great things about the Prusa Mini, it’s a hair pricier (and still requires modifications to print Nylons) and is regularly backordered. (Through I have a hunch in non pandemic times that may be less the case)
I love watching Deltas… I don’t like maintaining them.
My current holiday project is putting together a Voron V0 to see how close to MF performance it can get at the sub $500 price point. I love my prusa mk3s but the lack of enclosure (and the issues with electronics dealing with enclosing it…) hinders it. I’m also planning an experiment with how far I can go without using a heated bed since some groups (schools) get nervous about those. But it will not be as turn key as the Prusa Mini or Ender3 tbh.
I’ll second the AnyCubic i3 Mega S. I’ve had mine for about a year and it’s worked great printing PLA and ABS. I haven’t tried anything fancier than that though. It took all of half an hour to set up and hasn’t needed any significant maintenance yet.
We will never have the money, space or desire to purchase a water jet but, have over the last 5 years spent about 1000$ to have jobs done by a local shop. Water jetting is great. We do the lay out and cam for the vendor. Deliver the metal and G code file. Couple hours latter the vendor slips our job in with his production runs and parts are ready for pick up with in a day. We do have to do some clean up on bearing holes, and such. We try to do as much in house for the student experience.
We have 2 Ender 3’s that are used mostly by our middle school FTC teams. I replace the enders control board with Makerbase MKS Robin E3 E3D 32 bit boards Running Marlin 2.07. Also put Mellow labs NF Smart CR-10 all metal hot ends. Both parts are direct swap. The Enders are now very usable machines. 23$ and 33$ investment. The printers are so much better.
For CNC and printing it all starts with Cad. If your team doesn’t have the cad skills results from any CNC are going to be marginal. Teams need to invest in student cad skills to utilize the power of CNC.
Our experience with a sponsor using their CnC laser and brake was less than spectacular–the lasered parts were all great, but their bends were never, EVER accurate. Why? They built add-ons and accessories for transit busses, where if you were off on a bend by 1/4" you just pressed hard to get the pieces together during assembly, as the pieces were so big and non-finicky that it simply didn’t matter. The precision for FRC-sized pieces seemed nonexistent in their setup and their culture (because it simply didn’t need to be.)
I have five MPMDs, which I’ve spent a good amount of time upgrading and tuning–once you go through all the effort, they crank out small parts rather quickly within acceptable parameters, and only break/jam/randomly screw up 20% of the time… I’m still glad I have them, but definitely wouldn’t recommend that anyone get any Monoprice product ever.
I’ve had good experiences with their “core competency” in cheap AV cords (power, thin HDMI, etc) and other computer equipment - I’d use them for cables for a computer lab - but now we’re pretty far from the original topic
We have a fully upgraded X-Carve (9mm belts, stiffened x-axis, new z-axis, 800w vfd) and it can cut AL no problem, but no where as fast as as an Omio.
I invested in an Open Builds 1m^2 Workbee for my home shop and it cuts about 2-3x faster in AL than the fully upgraded X-Carve. The Workbee fully outfitted was about $2k which is less than we spent in the X-Carve with upgrades. The downside of the Workbee is that the kit is not as straight forward to put together as the X-Carve. The Workbee is also not as ridged as a steel router running on precision slides, but I find the cut time in AL reasonable especially since a comparable sized steel machine would be more than 2x the cost. I considered the Omio, but wanted a bigger machining area.
I used to work for a shipyard. We would joke that the small mark on a ship fitter’s tape measure was 1 inch. But they did did amazing work fitting big pieces of steel to always moving dimensions that make up a ship.
