CNC Router for Aluminum
 

We're in the market for a CNC router. For the most part this will be used for FRC which means lots of cutting aluminum plate (.125") and plastic. I know aluminum can be somewhat of a challenge. With that in mind what are your thoughts on the best 48" x 48" units out there that can be had for under $15K delivered?

We're looking at the ShopBot Buddy http://www.shopbottools.com/mProducts/shopbot_buddy.htm

and ShopBot Standard http://www.shopbottools.com/mProducts/prSstandard.htm

The Romax was recommended but it's build area is a little smaller than we'd like. http://romaxxcncrouters.com/store#!/...&sort=no rmal


I know we could make such a thing given enough effort. This is coming from a source, though, where we need to buy new.

Given that a lot of aluminum is in our future, are there better options?

Re: CNC Router for Aluminum
 

I have nothing but high praise for the ShopBot stuff. The 48" wide BT48 Buddy PRSstandard is a good size at 24 x 48 (unlikely you'll need to cut larger than that), and they definitely offer discounts to schools. The software they bundle with it - Vectric Vcarve Pro and PartWorks 3D are both powerful and intuitive, and work with SolidWorks and Inventor quite well.

the Alpha series uses close loop motors, and you're unlikely to need that for a robotics team or school. Open-loop steppers are sufficient for anything but the production environment.

With the router provided you'll be able to cut Aluminum (or wood or plastic) with the correct bit. Not super fast, but fast enough. For aluminum you should consider a mist coolant system and a vacuum dust/chip management system.

If you go for the spindle option, you'll gain some flexibility (because the spindle can spin at slower speeds than the router) but not a lot more cutting power. For me personally I would opt for the router, but for a school getting the funding for a spindle afterwards might be more hassle that it is worth.

If you can, definitely take their training. You will absolutely have to teach 2 or 3 kids each year to run and maintain the machine, somewhat like a lathe or mill, it is a complex and sensitive machine requiring some skill and knowledge to avoid damage or injury. Their training goes into a lot of detail, giving you a foundation for student lessons.

Also, give the ShopBot folks a call. They are happy to talk machining and can steer you in the right direction.

I know you need to buy new, so I won't mention the various 'kits' out there, but for others who might not be limited, one can build a machine similar to the 48 Buddy Standard for about $5k, including software & computer. I recommend the KRMx02 (Google it).

Re: CNC Router for Aluminum
 

We have a 4' x 8' shopbot with the spindle that we love. We've made a bunch of stuff on it, and we've used it with wood, foam, plastic, and up to .125 aluminum. The included partworks software is really powerful, but it's much easier to use than a normal CAM package. We've just started using Partworks 3d, which looks great too.

It took us a little while to figure out the best way to cut aluminum. Ours has the spindle, which has no trouble cutting aluminum. We've considered using the mist coolant, but the stuff smells bad and stays in the air, so we just squirt normal coolant on the bit as the thing cuts, and we don't use liquid coolant on thinner aluminum. We do use compressed air, through a vortex tube to cool the air, that helps get the chips out of the way.

The trick that we've found for cutting aluminum is not to go slow. We use an Onsrud O Single Flute aluminum bit, and go about 100 ipm through .125 plate, and I think the spindle rpm is near 14,000.

We have had one little issue with the bundled software. We've been exporting our part to cut as a PDF, then importing that PDF file in Partworks, and occasionally, it gets a little messed up with an edge in the wrong spot.

Re: CNC Router for Aluminum
 

So THIS is the secret to how all your robots look AMAZING!!! LOL

This is awesome! Now I just have to fine the money in the teams couch in the shop...THANKS!

Re: CNC Router for Aluminum
 

Dumb question: can a router be used like a mill to make wheels and cut box tubing?

Re: CNC Router for Aluminum
 

What are the power requirements for these machines (Shopbot & KRMx02)? I'm wondering if they can run on a single 120v 20A circuit.

Re: CNC Router for Aluminum
 

If you made really shallow passes probably, routers spin at much higher speed (and lower toques) and struggle if you try to cut to much off.

Re: CNC Router for Aluminum
 

Yes, albeit much more slowly than a mill. Also, you are limited by the kinds of bits available (since a router spins much too fast for an end mill) and how far they can stick out from the router nose.

Similar for box tubing: The reach of the bit is limited.

Typical limit is about an inch in aluminum.

Re: CNC Router for Aluminum
 

Thanks Don for the great info. Do you (or anyone else) have an opinion on the ShopBot Buddy, with it's moving work surface, vs the standard gantry ShopBot? Is one more accurate, versatile, or less fussy than another for FRC applications?

Re: CNC Router for Aluminum
 

They run on 120V 20A with the router. The spindles often need 240V

Re: CNC Router for Aluminum
 

As you said, solids are hard to do on a cnc router becuase they don't remove material all that quickly. That said, I have heard that 973 has used their router to do box tubing. However, they did make the router themselves, and it is quite beefy. Even then, I don't believe they run a lot of their tube through it.

Re: CNC Router for Aluminum
 

My team has a sheet metal sponsor. Would it be worth it to get a router or a CNC mill? We already have a lathe.

Cool that this thread came up, I just talked our money guys into a cnc router, but I'm looking for a 4x4 of the kit variety that our kids can put together for a summer project.

Re: CNC Router for Aluminum
 

We purchased this machine in the Fall and ran it this spring for gussetts, box tubing, aluminum, plastic, lexan, etc. http://probotix.com/FireBall_Meteor_cnc_router/

I believe that Lin will be in St. Louis for the Championships.

We ran ends for nearly all of our jobs this year in the 1/8" and 1/4" variety on mostly aluminum.

I would advise getting a Super PID to make the machine more user friendly.

We purchased the Mesh Cam and ArtCam softwares for the machine.

I would highly recommend this machine.

Norman

Re: CNC Router for Aluminum
 

What spindle/router do you use?

Re: CNC Router for Aluminum
 

We got the Bosch 1617EVS router and spindle. You will have to order the router separate. If you prefer Porter Cable, it requires the same spindle.

We also got the collets from Precise Bits.

Probotix customer service is great. They answer most questions/emails very quickly and are great on the phone as well.

Re: CNC Router for Aluminum
 

Check out cncrouterparts (dot com) for machines, they are located close to Seattle so you could go see the machines and get help, plus they are priced better than shopbot.

I have bought parts from them but I do not have a machine from them

Kelly

Re: CNC Router for Aluminum
 

How do you know what is the best router bit and spindle rpm for each application. Is there a website or resource that provides this information? It is just so confusing to find out which router bit and spindle rpm is best for each application.

Re: CNC Router for Aluminum
 

You can't go wrong with ShopBot! They are local to Durham, NC and they are one of our sponsors so we love them.

We cut our frame last year using them and the year before we had plates cut using them as well.

You can also use it to make awesome prototypes out of wood and polycarbonate.

All in all, a great machine and the software is easy to use and worth it.

Re: CNC Router for Aluminum
 

This was sent to me from one of the fablous mentors of 2471, Mean Machine. They have the Romax machine and are quite happy with it. It's just smaller than what I'm looking for. They use a single flute 1/8" bit for most things in aluminum.
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Free web app to calc feed and speed. Just a starting point.
http://zero-divide.net/index.php?page=fswizard

Some thoughts on CNC routing aluminum
http://blog.cnccookbook.com/2012/03/...tting-success/

Re: CNC Router for Aluminum
 

The moving gantry system is somewhat more versatile, but they are roughly equivalent. The gantry system also needs 'less' space since the outside edges of the machine are fixed, while the moving table needs some empty space to move into. But again, they're about the same. I can't say if one machine is better than the other though. Cost is a good indicator.
To be honest, a standard mill would be the next choice for me. CNC stuff is not a panacaea, you still need skill to run it, while a manual mill is a lot better educational value...especially if the mill is larger than the CNC version you're considering.
+1 on precise bits.
I have also bought parts from them but not a machine. However their CNC router is not as rigid as I believe necessary.Google "feeds and speeds". There are books and software that allow you to calculate this precisely. You also need to consider "chip load", which is specified by the bit manufacturer. Onsrud.com has some good info on that point, but do some research.

Repeating what I wrote before, the Kronos Robotics KRMx02 machine is probably the best on several levels. I built my 27 x 50 machine for well under $4k, but that was making several parts myself and using the FRC 80/20 discount. For just over $4k* you can get everything pre-made, making it a bolt-together project.

*This includes everything, like software, that's usually excluded from most other similar machines.

Re: CNC Router for Aluminum
 

Team 987 uses a shop bot buddy for much of our prototyping. It is a fantastic machine for the money. We regularly cut 1/2" aluminium using a 3/16 single flute spiral (50 passes). Of course the mill does a better job on the big stuff, but if your team can only afford one machine, it is a great investment.