[KriegKuts]

Greetings,

I have been tasked with creating a new router for mainly large format woodworking with aluminum jobs on occasion. 6x12'!! ( :banana I plan on using CNCRP rack and pinion and 8020 extrusion. We want the best quality electronics for speed/efficiency because this will be our only cnc router until we can expand. Spindle will be either a KL-2200 or a KL-4500 with appropriate VFD. I am open to options, however.
I have no clue if this is servo territory or nema 34 steppers, either way I would like to stick with gecko drives. I think servos would be good in the long run so any recommendations?

The idea will be to take the CNCRP4896 and enlarge it to 6 x 12'. How does this sound?

[KriegKuts]

Shameless bump.

[vtx1029]

Making it longer isn't really a problem other then you will run into having to have the extrusions shipped via freight. Making it wider not sure I'd ask Ahren about going 6' wide. Question is do you really need it that wide? Very few sheet products come wider then 5' wide that I know of. Ahren has kits for 5x10. If your cam program has a tiling feature that big of table isn't needed if you would only be doing an occasional job over 10'

I'd also look at going with real linear ways if your budget allows along with kellings ATC spindle before I'd go to servo's.

[harryn]

For commercial use, I would use either V bearings (example, pacific bearing) or a rolling bearing setup (example hiwin). A machine like that needs heavy duty components.

In commercial use, your parts need to be harder than what you are going to cut, so Al cutting (even periodic) means al rectangular steel frame.

I did the calculations for a 7 ft long gantry beam (for my hobby DIY use) and 6 x 8 x 1/4 in steel rectangle is in the right range for your project. A 14 ft beam (for the 10 ft direction) could use similar material if you floor mount it, or give it lots of midrange support.

Consider to mount the whole thing directly to the floor without an elevated table for something this heavy, since it will easily hit 2 000 lbs.

Geckodrive also now offers nema 34 motors, but they aren't on their web site yet. I just got one on Friday, and it's a beast. (as in good)

[KriegKuts]

Thank you for the responses.
From the keling website, it appears to me that a 3 axis servo package with 1125 oz. servos is only $100 more then a similar stepper package. Am I missing something here?

I am worried with the straightness of the 8020 since they state .12 over 20' length. Which linear solution could handle it better? Hiwin or CNCRP? The hiwin rails sound good and can come in 12' lengths, which size would I require? the 20mm? 25mm?

Also, how do the hiwins handle dust? My CNCRP carriages need constant maintenance to clean bearings if I am not using dust collection.

I will see if we can do 5x10'.

[RossMosh]

6' might be pushing the limits of a gantry made out of 8020. There are people building Joe's CNCs with long sticks of 8020 as the gantry. It might be worth spending the $75 just to find out if you can use extrusion on the gantry with reasonable tolerance.

As for the rails, you're going to fall over if you start looking into "real" linear rail systems. If this is a new business and it may fail, be smart. Build a machine that will work and go together and won't cost a fortune and a ton of time. If things work out, you'll go out and buy an industrial machine.

I'd call up/email Ahren from CNCRouterParts and ask him his opinion.

[ger21]

I am worried with the straightness of the 8020 since they state .12 over 20' length. Which linear solution could handle it better? Hiwin or CNCRP? The hiwin rails sound good and can come in 12' lengths, which size would I require? the 20mm? 25mm?

Nothing will be straight over 20ft. Gravity will pull anything more out of straight than .12" in 20ft. You're frame will need to keep the rails straight.

Hiwin rails are far superior to CNCRP skate bearings, but will probably cost 10x more.
If they'll be regularaly coated in dust, you may run into issues. They have special seal packages available with double end seals and scrapers to keep the dust out. Most large industrial routers use an automatic pressurized grease system on their linear rails which forces any dust out when the grease is injected. Greasing daily or weekly will do the same thing, as long as you stay on top of it. The more dusty the conditions, the more frequent they'll need to be greased.

I'd say 20mm rails are more than adequate.

[KriegKuts]

Hey guys,

We decided that the 5x10' size is going to be perfect. I will adapt the CNCRP router style with Hiwin rails. The roller bearings work fine on the fla-100 but they require too much maintenance. I would like some more info on the Hiwin dust management. Does it come with an oil nipple for pressurized oiling? We will use active dust collection, of course.

In regards to the keling ATC spindle. Has anyone ever used it and have any pictures of an installation? What support equipment would be required? pneumatics, drawbar, etc? I would allocate some table space for a fixed tool holder, IF we decide on the ATC spindle.

What is everyone's opinion regarding a solid metal table bolted to the concrete floor VS a wooden table to absorb some of the forces by having a little bit of movement?

What would be appropriate servos? (Prefer keling stuff) I'm pretty much set on gecko drives. Appropriate BOB?

More questions coming but that is all for now.

Thank you!

[harryn]

Servos are really nice, but you need to really know what you are getting into when you bite off that apple.

The good and bad of a servo can be stated simply - constant torque over the speed range. That means that it takes a dang powerful motor to get much torque, but you always have it available.

This forces you, nearly without exception, into serious gear reduction, and decent quality gear reduction is not all that cheap.

After reading about steppers and servos for 2 years, I finally felt comfortable about picking a stepper motor driver + motor, but if it were a servo setup, I would probably hire an advisor on the subject.

Just make sure you work out the forces involved before you build a router that your business will live and die on. There are some commercial units on craigslist in your size range for not too bad of pricing, if you have the space.

[jschaudt]

Kreig,
Definitely make the table legs and rail supports steel or aluminum tube. Wobble is not a good thing. As for the actual flat surface for milling, figure out if you are making a vacuum system or just going to have sacrifice material with clamps or screws. Our table has extruded aluminum rails that slide together lengthwise, and it allows us to have a clamp every 6 inches wide along the table. There are sign extrusions that can do this same thing with little modifications.

[osphoto]

For electronic kit, see http://www.candcnc.com/

I use his stuff and haven't had ANY problems. Stuff works! Support is amazing. I won't ever piece together another system after using his stuff.

[KriegKuts]

harryn - I was not aware of gear reduction being needed. I was planning on using the cncrp nema 34 rack/pinion system with a servo equivalent to a nema34 stepper.. If i cant use a servo then steppers will have to do.

jschaudt - Sacrifice material and clamps will be used. with the aluminum T-slot table. Option 2 might be a big steel plate with threaded screw holes but I don't know if this router could handle a surfacing cycle on steel plate.

osphoto - Do they have separate pieces? I rather put it all together and wire it up myself.

[ger21]

I would like some more info on the Hiwin dust management. Does it come with an oil nipple for pressurized oiling?

I think they come with zerk grease fittings standard. I'm not sure if there are any off the shelf pressurized lube systems available. If there are, they're probably very expensive. Try contacting a HiWin dealer, but you may need to fabricate one yourself.

In regards to the keling ATC spindle. Has anyone ever used it and have any pictures of an installation? What support equipment would be required? pneumatics, drawbar, etc? I would allocate some table space for a fixed tool holder, IF we decide on the ATC spindle.

This is the only Keling ATC spindle I've seen.
http://www.cnczone.com/forums/cnc_wo...ediculous.html

What is everyone's opinion regarding a solid metal table bolted to the concrete floor VS a wooden table to absorb some of the forces by having a little bit of movement?

Any movement is bad. If you build a wood table, you don't want it to move. Big fast routers can apply tremendous forces when changing directions. Anything that moves a little, will sooner or later move a lot.

What would be appropriate servos? (Prefer keling stuff) I'm pretty much set on gecko drives. Appropriate BOB? .................................................. .............................I was not aware of gear reduction being needed. I was planning on using the cncrp nema 34 rack/pinion system with a servo equivalent to a nema34 stepper.

The drive system components all need to be a matched set, designed around a target performance goal.

The CNCRP Nema 34 rack and pinion uses a 2:1 reduction. There smaller rack and pinion uses a 3:1 reduction.

For a given motor frame size, steppers tend to have much more torque than servos. Servos have much higher rpm's, though, so you typically use a smaller servo with 5:1 or higher reduction. This gives you more resolution, and more power than a stepper at similar rpm's.
Basically, a 100oz servo geared 5:1 running at 3000 rpm will have more power than a 500oz stepper at 600 rpm.

[ahren]

I would not use our Nema 34 R&P systems with a servo motor -- there is not enough reduction to get adequate power from the servo.

I would humbly suggest that you consider our Nema 34 motors -- they are low inductance, so they don't require massive high voltage supplies, and provide good torque out to a pretty high RPM range. Feel free to contact us directly through our website -- I'd be happy to discuss your application with you.

Best regards,

Ahren
CNCRouterParts

[KriegKuts]

Ok,

Stiff frame, got it. I will design a table that will end up bolted to the floor. Going to use either wood or steel. Leaning towards steel.

Would the KL-4500 spindle be considered overkill on this project compared to the KL-2200? the 380V single phase is no problem, we can run a line into the shop. I am drooling over the ATC version and will discuss this with my colleague. It just so happens I have some 24V air valves already from scrapping an old monarch vmc and I understand the basic tool change theory.

Ahren - Thanks for your input. I will go with the steppers. I would like to squeeze every last bit of performance out of the motors however. What do you suggest? I was thinking of powering the steppers using the max voltage the gecko G213V drive can handle which is 80V at 7A. Is this a sane idea?

[ahren]

7A for sure, but optimum voltage is 32*sqrt(L) for most steppers. In the case of our 960 oz-in motors, this is about 45V, so 48V supplies work really well. Going more than this won't help much and will cause the motors to run hot.

Best regards,

Ahren
CNCRouterParts

[KriegKuts]

Thanks ahren. +48 is easier to source anyway. Today I get to find out if we can afford an atc. Ill keep y'all posted.

[KriegKuts]

We decided to wait till the end of the build to buy the appropriate spindle. Projected start date is October 1st. Once the parts are ordered I'm optimistic to be done in about 3 weeks with the shop (which will likely be a converted 4 car garage) and the router buildup. Until then, I have to redesign the router for hiwin rails and price everything out.

[vtx1029]

I've been wanting to build a tool changer as well. For the tooling rack I would think about having a the rack extend out from under the gantry at the back end of the table. While this may limit you some on how long of tool you can mount up for a production run you would gain in by using wasted space and not have to extend the length of your table. It could be easily and cheaply done with a couple of bimba cylinders.