Help with CNC "router"

[DonRotolo]

Originally Posted by AdamHeard

The biggest variable being what to do for a spindle, followed by what controllers to buy for our existing (200V 100-300W) AC servomotors.

Spindle: You can initially go with a wood router (1 to 1.5 HP) with a variable speed controller, and stick with 1/4" shank mills, to save costs and get a feel for what it can do. Easily mills aluminum, steel not so much.

Later, you can engineer a real quill once you learn the kinds of rigidity and precision required. For now, a reasonably rigid Z axis with perhaps 6-12" of travel will be fine. (Trust me: approach this like a robot - build a low-investment prototype first, then redesign after learning the lessons)

Controllers: Obviously you use a computer to 'control' it, with software like MACH3. What you're looking for a nice "driver" board, and possibly a power supply as well. eBay can be your friend here, several companies such as Omron, Mitsubishi, Panasonic, etc. make boards that will drive your motors. Plan on looking carefully for one that drives 200V AC at over 1.1 A (220W - buy one a little bigger). For three phases expect to spend $300-800, more if new.

There's a lot of expertise here, keep asking questions.

[AdamHeard]

So, if we were to mount a spindle on the "Y" which is really the Z in the current orientation, we'd get very limited travel.

But what if we turned the whole thing over, and hung the Z down below it? We'd still geometrically get the same travel, but do these need to be run in the orientation they were designed for?

[sanddrag]

A router is certainly the cheapest option, but I'd be worried it's RPM would be a little fast, it's bearings might not last for heavy milling in aluminum, it probably wouldn't take larger endmills, and it would be really loud.

There's this spindle but it's not cheap and a little on the small side. Also, it could stand to be a little faster. Nice thing is, it's a complete unit and it's R8.

You could use a Tormach spindle assembly which is pretty nice (they have two different ones), but it would run you about $1100. It's a bit large. I'm not sure how it would fit in with the scale of your machine.

I'm not aware of any other spindle assemblies for sale separately. You could contact some mill manufacturers though such as Industrial Hobbies or LatheMaster and see if they'd be willing to sell you just a spindle assembly.

Of course, with all of these options, you'd still need a Z-axis.

[Thermal]

Originally Posted by sanddrag

A router is certainly the cheapest option, but I'd be worried it's RPM would be a little fast, it's bearings might not last for heavy milling in aluminum, it probably wouldn't take larger endmills, and it would be really loud.

There's this spindle but it's not cheap and a little on the small side. Also, it could stand to be a little faster. Nice thing is, it's a complete unit and it's R8.

You could use a Tormach spindle assembly which is pretty nice (they have two different ones), but it would run you about $1100. It's a bit large. I'm not sure how it would fit in with the scale of your machine.

I'm not aware of any other spindle assemblies for sale separately. You could contact some mill manufacturers though such as Industrial Hobbies or LatheMaster and see if they'd be willing to sell you just a spindle assembly.

Of course, with all of these options, you'd still need a Z-axis.

Wood routers are quite capable of sheet aluminum work but you have to get a little creative about it. http://www.vhipe.com/product-private/SuperPID.htm is a great tool for that.

You're correct about the bearings though, heavy aluminum work will destroy wood router bearings in a few months. Handily though, replacement bearings are relatively cheap and not too difficult to replace.

[DonRotolo]

Originally Posted by AdamHeard

do these need to be run in the orientation they were designed for?

Depends, some can, some cannot. Consider moving the material in X and Y beneath a fixed gantry for Z

Originally Posted by Thermal

Wood routers are quite capable of sheet aluminum work but you have to get a little creative about it. http://www.vhipe.com/product-private/SuperPID.htm is a great tool for that.

You're correct about the bearings though, heavy aluminum work will destroy wood router bearings in a few months. Handily though, replacement bearings are relatively cheap and not too difficult to replace.

Yes, so the wood router is a temporary solution ONLY, a $50 investment to get a feel for the machine on the cheap. Then a real spindle can be developed, after the hard lessons have been learned inexpensively.

[AdamHeard]

Looks like we might have the controller with it, need to poke around more.

We came up with the basic simplest option. Use the x-y as is, sell the motors on it, make a basic z-axis w/ spindle, and then buy one of those high powered stepper motor, software and controller packages. This would get us about 16x48" of travel.

We still have more research to do, but we're committed to using this guy during our 2012 season.

[Mr. Lim]

Originally Posted by Thermal

Wood routers are quite capable of sheet aluminum work but you have to get a little creative about it. http://www.vhipe.com/product-private/SuperPID.htm is a great tool for that.

You're correct about the bearings though, heavy aluminum work will destroy wood router bearings in a few months. Handily though, replacement bearings are relatively cheap and not too difficult to replace.

Team 188 has been cutting aluminum on a CNC router equipped with a wood router as a spindle for a number of years with a lot of success. Patience, conservative cut depths/feed speeds, a good cutter, and someone to stand over it with a vacuum to clear chips, and coolant are key. Don't expect to be able to hold tolerances to press-fit bearings though!

Here are the cutters that we swear by, and 188 also has adopted:
http://www.onsrud.com/xdoc/SuperO

We run them at 18,000 RPM. I think 188's wood router is a fixed speed at 24,000 RPM which is a bit fast I think, but it is possible. The single flute in the cutter makes a big difference in being able to run at these speeds.

[Thermal]

Originally Posted by Mr. Lim

Team 188 has been cutting aluminum on a CNC router equipped with a wood router as a spindle for a number of years with a lot of success. Patience, conservative cut depths/feed speeds, a good cutter, and someone to stand over it with a vacuum to clear chips, and coolant are key. Don't expect to be able to hold tolerances to press-fit bearings though!

Here are the cutters that we swear by, and 188 also has adopted:
http://www.onsrud.com/xdoc/SuperO

We run them at 18,000 RPM. I think 188's wood router is a fixed speed at 24,000 RPM which is a bit fast I think, but it is possible. The single flute in the cutter makes a big difference in being able to run at these speeds.

You should create an effective dust shoe, then you don't even need a person to stand around with a vacc in hand

[R.C.]

Originally Posted by Mr. Lim

Team 188 has been cutting aluminum on a CNC router equipped with a wood router as a spindle for a number of years with a lot of success. Patience, conservative cut depths/feed speeds, a good cutter, and someone to stand over it with a vacuum to clear chips, and coolant are key. Don't expect to be able to hold tolerances to press-fit bearings though!

Here are the cutters that we swear by, and 188 also has adopted:
http://www.onsrud.com/xdoc/SuperO

We run them at 18,000 RPM. I think 188's wood router is a fixed speed at 24,000 RPM which is a bit fast I think, but it is possible. The single flute in the cutter makes a big difference in being able to run at these speeds.

Mr Lim, we do the exact same thing but we cap out at 14k rpms. Also we just added "compressed air" and just dry cut aluminum. With two flutes you need coolant but with single flutes you don't even need coolant.

For our machine, the reseller does not advice coolant in any spray form but they recommend using drops shown here:

http://www.techno-isel.com/h850/html...ection_22.html

-RC

[AdamHeard]

We were able to find the controller and manual for it, haven't been able to test yet (Need to find 220 single phase...).

The manual explains a lot, especially the lack of spindle and odd axis arrangement.

It actually is a Yamaha "FLIP Series" robot. Which appears to be a stripped down and repackaged router. So, although it looks like the 2 of the 3 axis from a large gantry router, this was it's original configuration.

[DonRotolo]

Originally Posted by AdamHeard

(Need to find 220 single phase...)

You know that every house & building in North America that has "110 volts" also has 220 single phase, right?

Finding the book was HUGE, that'll almost guarantee success...even if you decide to use different hardware.

[AdamHeard]

Originally Posted by DonRotolo

You know that every house & building in North America that has "110 volts" also has 220 single phase, right?

Finding the book was HUGE, that'll almost guarantee success...even if you decide to use different hardware.

Yes, it's just the hooking up that we need some help with, we have 220 single for one of our lathes but there is no plug, it's hard wired. We need to bring in some outside help to make it happen. I don't feel like a few students and I wiring 220 is something we should be doing.

[DonRotolo]

Originally Posted by AdamHeard

I don't feel like a few students and I wiring 220 is something we should be doing.

Eh, the worst that could happen is you get killed

Um, yeah. Better safe than sorry. 220 is nothing when you have the expertise, but WAY deadly and not at all forgiving of mistakes. Probably easier to bring the whole thing to someone's house, where there's a plug wired for 220 already, and just wire it up with the correct plug.

[Mr. Lim]

A spindle option for you:
http://www.a2mc-cnc.com/Spindles.html

We use the Elte 3HP @ 18,000 RPM and have been quite happy with it. We also have an auto-mister, which is a very nice feature for cutting aluminum. We cut up to 1/4" thick plate on our setup - multiple passes of course.

AXYZ Router (http://www.axyz.com/) might even quote you an entire Z assembly + spindle. They build complete CNCs based on the A2MC controller, and do some custom work as well. Maybe they can give you a pre-fabbed Z assembly + spindle, and just let you figure out how to mod it to mount it on your X/Y gantry. If you go this route, again I'd highly recommend the mister.

As an aside, here are some options for stepper controllers if you don't get yours working, or if the old ones don't support ModBus:
http://www.a2mc-cnc.com/motors_drives.html