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?