[dinkyguitar]

Hi All,

My cnc will have a 36" x 24" working area, all aluminum, 20mm round linear supported rails, and 16mm ballscrews.

I plan on milling wood mostly, with some aluminum.

My question is, is the G540 w/ 381oz-in motors strong enough?

I'm planning on ordering from Keling. They also has the same setup but with nema 34 465oz-in motors. Or should I get individual gecko drives..

Since I'm new, I'm not sure what to get....

dinkyguitar

[Pplug]

Yes get the g540 with the 381oz motors with a 48v power supply. That will cut through wood and it will do it fast! I've used the setup with 10mm pitched ballscrews and 5 mm ballscrews. That combination of motors and drivers will be strong enough and incredibly fast for wood with 10 mm pitched screws. It will be incredibly powerful and pretty quick with 5mm pitched screws.

The g540 will also help with simplifying wiring your limit switches and touch sensor/probe.

[johnmac]

For best results, "gear" the machine so you get 1 inch of travel from about 3 turns of the motor. The stepper motors produce most power when spinning slow, so don't be tempted to "gear it down" for extra power or you will simply have a slow machine.

I think the G540 drive and 381 oz motors should be OK.

I have 425 oz motors and ball screws. At slow to medium motor speed, I cannot stop the gantry by holding onto it. But I can at high speed.


John

[Pplug]

The 425 oz motors are not as good as the 381 oz motors. They loose torque faster at a slower speed and you would need a larger voltage power supply than the g540 can take to utilize them completely.

We don't know what your thread pitch is so I can't give you a perfect recommendation for the motors but the 381 oz motors pretty much max out the g540. I would stick with those.

[dinkyguitar]

Thanks for your help!!

Pplug,

Here are the ball screws I have. The specs say "lead 5". Not sure what that means though

Any suggestions or best place I can get the whole package? 3axis

dinkyguitar

[BanduraMaker]

You probably have 5mm/rev screws. This will give you tons of force but it will limit your top speed some.

I have the Kelling 381 kit with 10mm lead screws and my all aluminum machine has a top speed of about 400ipm on the big axis.

[Pplug]

With good linear rails and construction techniques, you can get better than 250 ipm running your machine until screw whip comes to play. On a 4x4' machine with 5mm pitched screws I can get up to 270 ipm before screw whip gets out of control. With the reduced length of you're screws I would expect it to be much faster.


I bought mine from Keling. At the time they had the best deal. Not sure now....

[Wyndham]

Glen, I've been looking and learning what I can and if I understand the "Build your own cnc" site with the hardware and plans. If I cut out the MDF board, get a spindle w/PS and software, I'll have the basics for a good wood carving sign machine.
When you say Big Axis what size are you referring to.
I'm bad to overlook things when I'm new to a new endeavor. I have the computer, a single core athlon 1.7 ghz with 1 gig mem using win xp. I'll likely get mach 3 and vectrics vcut or use Linuxcnc. Have more to learn on the software side as well.
Thanks for your post.
Wyndham

[BanduraMaker]

When you say Big Axis what size are you referring to.

I'm referring to the long axis on which the gantry moves. I've got a 2510 ballscrew on that axis which as I mentioned, is reliable at 400ipm. I hear guys with 2525 are getting 800+. My "Y" and Z axis have 1610 screws and are good for about 500ipm+ but, I run them at 450

[Pplug]

Are you planing on making your router out of mdf?

Btw, my name is Chris, and I live in Glen Spey, NY.

[Wyndham]

Hey Chris, sorry about that. I don't have specific plans right now. I most likely will learn all I can an plan a build at the first of the year.
I have a pottery in Seagrove NC and have an extra room that I could put a 2'x3' router bed and have enough working room around it.
At first I thought about a Zen 12x12 but for not that much more money I think a 2'x3' DIY would be possible
The MDF comes from what I saw on the "buildyourcnc" There a ton of stuff I don't know about but digging in a bit at a time.
Wyndham

[Pplug]

Your not the first and wont be the last! when thinking about the frame, remember it needs to be incredibly ridged with a lot of mass to cut down on vibrations and shaking. My fixed base router has a 500lb base. The moving mass on the x and y axis cause the whole router to buck and shake!

[ssutton]

I am running a G540 with 280 oz/in nema 23 motors and a rack and pinion setup and 4:1 ratio. The gantry is steel and aluminum and is 62" wide and > 100 pounds. The power of the system is incredible, I have NEVER stalled it out when cutting even deep cuts and good speed. When the motors first arrived I thought that they would never push my machine because they looked so small. I can run up to 400 ipm but I never cut over 175 ipm.

Scott

[Walky]

Dinkyguitar, that G540+381ozin Keling combination is a really good driver/motor match, I made a machine using those components (and a 48V PSU), with 16mm round rails and 16mm ballscrews (10mm lead on x/y, 5mm lead on Z). For that size I wouldn't go with 5mm lead for X/Y as it would increase whipping a lot. This build doesn't even use the motors at full current (IIRC I used about 3A for X/Y and 2.8A for Z).

There are some videos about halfway into the thread:

http://www.cnczone.com/forums/diy-cn...w_machine.html

[dinkyguitar]

Thanks Walky,

Unfortunately, I bought my ballscrews a few months ago before I came across whipping, and all my ballscrews are 5mm.

Cool video's! Looks like it has lots of speed.

dinky,

[Pplug]

Theo e thing you have going for you is the length of the screws. The shorter they are, the less whipping will occur.

[Walky]

Thanks Walky,

Unfortunately, I bought my ballscrews a few months ago before I came across whipping, and all my ballscrews are 5mm.

Cool video's! Looks like it has lots of speed.

dinky,

It's not that bad, really, you'll have extra resolution and torque, but at the cost of slower rapids. I'm pretty sure the actual cutting speeds will be quite good anyway, perhaps as good as with the 1610 ballscrews speaking practically, considering many of us use cutting feeds way below what our machines can manage. How much will the slower rapids affect total job times will depend on the nature of each job.

[Walky]

I'm referring to the long axis on which the gantry moves. I've got a 2510 ballscrew on that axis which as I mentioned, is reliable at 400ipm. I hear guys with 2525 are getting 800+. My "Y" and Z axis have 1610 screws and are good for about 500ipm+ but, I run them at 450

Can you please tell me how long is your 2510 ballscrew and how different are your acceleration settings compared to the 1610 axes? I've been considering the 2510 for the future but I'm not sure about how much can its weight compromise acceleration, and I'm also not sure about how long I can go with it, though the Nook calculator can somehow work as a crude reference (I'd love to get close to 2500mm travel even it it means using slower rapids, even 2000mm would be OK, I guess...). Considering I've successfully used 1610 at about 1200mm, using 2510 at 2000mm with more conservative speeds seems feasible, but I'm not so sure at 2500mm. 2525 seems too much of a resolution tradeoff to me.

Edit: I checked your threads and found out you got a Raptor with the 2510 on a 36" axis, which seems pretty beefy. I wonder if anyone here has used those on a longer axis.