CNC Router for Aluminum

[bigbeezy]

Our team has been extremely fortunate to have the use of a couple waterjets at our main sponsor's facility. This has been extremely useful over the years, however we are consistently faced with relatively long lead times, down machines, sick operators, etc. We hold off on manufacturing parts until nearly everything is designed so that everything can be cut at once. Which means at times we have parts waiting over 2 weeks before they are in hand, and you better hope that they work... So, we are looking at purchasing a CNC Router to be able to cut aluminum sheet in house. We feel that this could be a game changer for our team by speeding up prototyping, manufacturing, improving quality, etc.

Does anyone have any suggestions on a CNC Router? I'd like to not spend a fortune but don't want some cheap machine that will break in a year. It should be fairly straight forward to operate. Most of the time it would cut 1/8" or less. I was thinking one that was 2'x3' would be a good size. Any experience and suggestions you might have would be greatly appreciated.

[Steven Smith]

Search around and you'll find a variety of posts on this.
Speeds and Feeds for Aluminum
Second post by Don Rotolo on speeds/feeds
Building your own CNC - I noted I was going to build the Kronos, but went with CNC Router parts due to purchasing woes with the school

FRC3005's primary CNC workhorse right now is a CNC Router Parts 4'x8' PRO line gantry (V groove bearings). We got it late due to the school purchase process, installed ~3rd week of December. We did manage to cut aluminum, just at very shallow passes (0.01" to 0.02" DOC). The single biggest improvement that took us from pretty hit or miss performance to reasonable performance was getting a high quality, single flute "O" bit which is better for chip evacuation. In addition, we'd chase the bit with a little lube/coolant to keep temperatures down. (it is possible to dry cut on a machine set up properly, ours wasn't)

Right now, I'm working on a series of improvements to the table (will be posting Youtube videos) in hopes to get it more student friendly for next year. Primarily, we CNC routed a thien baffle based dust collector, which will keep from recutting chips that spread on the table, as well as installed an air assist with compressed air that blasts the bit for chip evacuation. I might end up installing a mist coolant to it as well. We also surfaced the table (didn't get a chance with basically starting on the router during build season), which helps ensure a consistent DOC. One last critical thing for cutting aluminum (or anything really) is workholding. You need enough rigidity in your fixturing and gantry to ensure your piece isn't vibrating with the cut, which just leads to massive heating and failure of your bit.

Feel free to reach out via PM or through this thread if you have any questions. CNC routers are not without their flaws, but I think the ability to do wood/plastic/aluminum is great for an FRC team. It's great for robot related projects as well as shop improvements or student side projects.

Edit: Also, I think that my total bill from CNC router parts was ~$6600. That included all the auto Z features, limit switches, upgraded controls, yada yada. I spent maybe $200 on steel to weld out a frame for it. There are cheaper options out there, but this CNC router arrived as a kit that we were able to bolt together in ~10-15 hours of work.

If I did it all again, I'd definitely consider swapping to the 4x4 model, which should run ~$1000 cheaper. I'm currently running the basic Cut2D software they offer for ~$150, but I'd like to switch to HSM Works which we all get for free through FRC... and see if it is overkill for the application.

[Jacob Bendicksen]

I'm minimally involved with our CNCing, but from what I've heard from my mechanical buddies, we're happy with our ShopBot Buddy. 2'x3' cutting surface, reasonably priced (for a CNC router, so still not cheap), and not too hard to use (though VCarve is another story).

[RoboChair]

1678 is looking forward to purchasing a Velox CNC 4'x4' router sometime in the next week or so with some grant money. Really knowledgeable people working there. You can build out exactly what you need based on features you want or what you are willing to handle yourselves(we are making the table and table top for it). The school discount doesn't hurt either. After tax and shipping it's about $7000.

[cbale2000]

Anyone have any thoughts on something like a Shapeoko or an X-Carve?

These seem to be a much lower cost alternative to a lot of CNC routers I've seen and it looks like a reasonable project for a team to assemble.

[techhelpbb]

Originally Posted by cbale2000

Anyone have any thoughts on something like a Shapeoko or an X-Carve?

These seem to be a much lower cost alternative to a lot of CNC routers I've seen and it looks like a reasonable project for a team to assemble.

Both are using stepper motors.
With open-loop steppers you have to move slowly to stay in the band where the stepper motor torque is high.
Move too quickly and you'll miss steps which could ruin the work piece.

Used with O-Flute cutters you can often cut aluminum with some basic mist coolant but be aware that if your spindle is open-loop as well you might have some interesting moments getting the speeds and feeds right to insure the longevity of the tool and the quality of the cuts.

The Shapeoko uses a small router which may or may not have a standard collet tool holding system while the x-Carve has a ER11 collet equipped spindle. Extending the tool out from the spindle always risks some run out either way. To put this in perspective the little Sherlines, Taigs and MaxNC mills often can be gotten with head stocks and spindles that can run ER16 collets (larger diameter tools and more powerful spindle motors at lower RPMs more suitable for the low speed feeds you may be limited to).

I suspect you can upgrade the Shapeoko to a closed-loop spindle with a SuperPID. Turns out there's a YouTube video for that. This would allow the router to run at a lower speed and to maintain it's speed even under cutting load.

Due to rigidity a Tormach or cheap retrofitted vertical mill is better for general aluminum cutting (on smaller plates) than this would be. Still plenty of people use bridge mills to: drill, route and cut aluminum plate even if it takes light passes to do it especially if the plates in question are large (I've worked plates as large as 4'x8' in a ShopBot).

I have some Velox pieces on some of my CNC rigs. Take a good look at the length of the steppers Velox is using versus these. Notice those steppers are double as long? That's because those are higher power steppers. The higher the power the steppers the more likely as they loss torque with increased RPM they will still have enough torque to finish the job without missing steps.

There's not much stopping someone from getting a Taig spindle cartridge some cog belts and a 1/3HP motor or servo motor and control and making a Taig style head assembly for a bridge mill - just make sure the bridge can handle the side loading.

[asid61]

The old Shapeoko 2 could cut aluminum, albeit slowly, but the Shapeoko 3 seems to charge through it much faster out of the box. Nowhere near the level of an industrial machine, but good enough for FRC (depending on how many parts you have to make). There are videos on youtube of both.

[TomThompson]

We have used a CNC plasma cutter for some aluminum work. The cuts aren't as fine as what you would get with laser or water jet. I would think a router would be pretty slow on aluminum.

[Coach Norm]

Our program has been using the Probotix's Meteor http://www.probotix.com/METEOR-CNC-ROUTER?search=meteor

I also have one of the http://www.probotix.com/V90-MK2 at one of our middle schools.

We have used the Meteor machine for two years now. We use it for aluminum sheet and stock up to 1/2" as well as all kinds of plastic.

The machine comes assembled in the crate. They offer some options on the router that you provide yourself on the larger machines.
We purchased collets from http://www.precisebits.com/

Both companies are great to work with.


Let me know if you have any questions.

[DonRotolo]

I've since revised my feeds down by about half with good results - the cuts are cleaner and not as demanding on my cooling system - but other than that what I wrote is still OK.

Team 223 has has a lot of luck with their CAMaster Stinger (not sure if it is a Stinger 2 or a Stinger 3) using Onsrud aluminum bits and feeds around 20 IPM. Ping CD User "rcoren22" (who is off for the summer) for his take on the machine.

2' x 3' might seem plenty big, but wait until it isn't. Just a hair larger (like 48 x 28) has a lot of additional uses.

[SJaladi]

Originally Posted by Coach Norm

Our program has been using the Probotix's Meteor http://www.probotix.com/METEOR-CNC-ROUTER?search=meteor

I also have one of the http://www.probotix.com/V90-MK2 at one of our middle schools.

We have used the Meteor machine for two years now. We use it for aluminum sheet and stock up to 1/2" as well as all kinds of plastic.

The machine comes assembled in the crate. They offer some options on the router that you provide yourself on the larger machines.
We purchased collets from http://www.precisebits.com/

Both companies are great to work with.


Let me know if you have any questions.

For your CNC router, which router/spindle are you using and did Probotix provide it or did you have to purchase it separately?

[Coach Norm]

Originally Posted by SJaladi

For your CNC router, which router/spindle are you using and did Probotix provide it or did you have to purchase it separately?

We went with the Bosch 1617EVS Router but it uses the same spindle head as the Porter Cable. We purchased it separately from Home Depot or Lowes online.

[SJaladi]

Originally Posted by Coach Norm

We went with the Bosch 1617EVS Router but it uses the same spindle head as the Porter Cable. We purchased it separately from Home Depot or Lowes online.

Excellent! Our shop has no access to a 220V power supply and the school is not very cooperative in getting one put in so a CNC machine that uses 110V is exactly what we need. With any luck we'll be getting ours ordered very soon!

[BBray_T1296]

Originally Posted by SJaladi

Excellent! Our shop has no access to a 220V power supply and the school is not very cooperative in getting one put in

Tell us about it . Our school maintenance guy went so far as to say that 220V/440V doesn't exist anywhere in our school!

(how does the building ever cool down!?)

[Fusion_Clint]

We picked up a Velox router 50" X 50" with a 4 HP 220V spindle and absolutely love it. No problem at all with 6061 Aluminum plate. I think the total price with shipping was $13K.

http://www.veloxcnc.com/vr5050x_cnc_router_4_x_4.asp