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The machine, all steel made, the table is 48 x 48 . The gantry weighs in at about 60+lbs with 2 motors driving the "Y" axis. I would like to know which G540 kit would be best suited for this size machine, either the G540 with the 381oz motors or the G540 with 570oz motors. I will be using this machine for wood and soft metal parts making.
Thank you for your help.
Hi CS6 - I made my first router with the G540. They are good but if you run 4 axes they need to be limited to <3A per axis (read the manual and from my experience with them faulting at max current settings) so that means a 570ozin motor won't achieve its full torque. A large N23-425ozin motor can pull 4A plus. So is the 570ozin a N34? The 381ozin motor is a better fit at around 3A but 267ozin motors are quoted at 3A so again you may not get full torque from the 381 motor... . The Gecko drivers do provide a good smooth motion. Have a look at the Knighthawk (KH) controller from CNC3D. They are rated at 4.5A per axis. They are a better integrated unit like the G540, run smooth at 36V, uses wireless technology, no soldering and I'm impressed so far with them. I think they are several steps ahead of the G540s and the sperate component systems I have built. I think by the time you buy the control software, motion controller etc the price will be the similar and you can use the big motors (edit see below)... Plus you can use your phone as a pendant!! Bonus...and it has a laser output so one of my routers has a 10W laser on it as well.. .Peter
https://www.cnc3d.com.au/nighthawkcnc-controller
Just checked - A G540 plus UC100 plus UCCNC license would cost $790AUD and a Knighthawk would cost $499AUD which does more than the combo. The KH looks great value...
Thank you peteeng, below are the 2 kits I am questioning.
Both kits are N23 motors, 4 axis kits, and both are optimized for the G540 at 3.5A current.
https://www.automationtechnologiesin...-110vac-220vac
https://www.automationtechnologiesin...tor-cnc-router
Hi CS6 - Sorry they maybe "market optimised" but the gecko cannot supply the quoted 3.5A current when used in 4 axis application. That's my experience not just the book data. I had to modify the gecko board to correct overcurrent faulting under the gecko technicians advice. Plus add limiting current resistors, so never achieved the motors full capacity. This was disappointing at the time but that's part of the learning curve. Plus you still have to decide on motion controllers and machine controllers. Buying good motors is the easy part of the equation. Peter
edit - I looked up the spec of the motors they are high inductance motors so are cheap motors 6.4mH. Buying separate motors say from stepperonline gives you 3.8mH motors which will perform much better and they are only $23USD. Often those kits are not good value for the buyer.
Hi,
Gecko certainly have a good reptation for quality and longevity, but I question your choice of G540. Not because of any failing of the G540, but that it is limited
to 50VDC. You should aim higher. There are many drivers, Gecko among them, that do 80VDC and increasingly quite a few that will do 110VDC.
All steppers lose torque the faster they go, it's the physics of steppers, and no avoiding it. Inductance of the stepper windings is a good indicator as to how bad that
torque degradation will be. The lower the inductance the better. Choosing low inductance steppers is the first choice for good CNC operation.
The next line of defense is to use the highest voltage you possibly can to drive the steppers. 50VDC is these days considered pretty anemic.
Both of the kits you have linked to use KL23H2100-35-4B steppers and they have 6.4mH inductance, which is poor, even very poor, by my reckoning.
For 23/24 size steppers, 1mH -2mH, 1mH preferred and reject anything over 2mH.
For 34 size steppers, 2mH-4mH, 2mH preferred and reject anything over 4mH.
So, I'm sorry to say that neither of the kits that you have linked to are very good in my opinion. You could do a lot better for the same sum of money.
Craig
Hi CS6 - Looking at stepperonline:
4xN23 large motors - $92USD
power supply 48V 10A $46USD and buying a G540 local $317USD means it costs $455 for same system with good motors. Plus some wire - Seems the kits is a bit too many $$$ The cheaper kit costs $597USD I'm $100 ahead... Then there's the Nighthawk Peter
Hi,
there is another thread running (https://www.cnczone.com/forums/milli...cnc-forum.html ) and that guy linked to this stepper, now it is 34 size, but look at its inductance of only 2.5mH. This thing rocks....
https://www.omc-stepperonline.com/p-...s-34hp29-6004s
This would be my choice of driver, its not a Gecko but it will do the trick. Note that if you have a three axis machine you will need three of them. It somewhat less convenient than the G540, but bang for yourQuote:
Hi,
the more I think on it the 4.5Nm, 2.5mH stepper above (34HP29-6004S) with 80VDC or 90VDC driving it will handily do 1000rpm and STILL retain half its torque, say 2.25Nm,
and may even do better, say 1250rpm or 1500rpm with still useful torque, approaching 2Nm.
If they were direct connected to 5mm pitch screws that would equate to rapids of 5000mm/min (1000rpm) to 7500mm/min (1500rpm), both of which are very respectable
in a smallish hobby machine and yet still have something like 5kN of thrust at low speed with a 5mm pitch screw of 16mm diameter.
I really do think this model motor is the hands down winner. Don't mess around with a small motor for the X and Y. If the larger 34 size motor will fit then bung them in there and let the fun begin!
Craig
buck these things are many times better value for money.
https://www.omc-stepperonline.com/y-...4-motor-dm860y
Last thing is don't mess around with switchmode power supplies, a linear supply is a far better choice:
https://www.antekinc.com/ps-10n80-10...-power-supply/
Just as a comparison:
1 Antek 1000W power supply $158
3 DM860Y driver at $29 each or $87 for three
3 34HP29-6004S 34Size (4.5Nm 2.5mH) steppers at $51 each or $153 for three
TOTAL $396
Quite a cost saving, over even the cheapest kit you listed and many MANY times better components.
Craig