[fretman_2]

A few more pics...a little mockup. I'll have a different arrangement for the motor mount along with drive screw bearings at each end.

Attachment 320818

Attachment 320816

[fretman_2]

How about this driver for my 5.4mH Nema 23 motors...

MA860H Stepper Motor Driver Max 80VAC or 110VDC with 2.4-7.2A|US055|Stepper Motor Drivers

[Louis_Cannell]

What voltage are you considering running at?

[fretman_2]

Louis...I guess that's what I'm asking...what voltage should I run those at? I understand that if I'm to get the best performance from those motors I need to run them in the neighborhood of 70vdc. Could I run them ok with a 48vdc power supply? I understand I may not get the best high speed performance. If I can get by with a lower voltage maybe I could run the dm524 drivers.

Tnx,

[ger21]

Speed is proportional to voltage, so at 48V, you'd get about 2/3 the speed that you'd get at 70V.

I'd highly recommend getting digital drives, even if it costs an extra $75 or so.

[Louis_Cannell]

I am running at 48v with 542 and 425oz nema 23's and enough speed and torque to tear my aliminium machine to pieces if let loose without care, (Had one repair after slave axis mishap) I cannot see you being able to use more than that on your build I would say 48v is plenty of speed and tirque for your needs, my machine weighs in considerably heavier with 25-30mm plate etc plus 6mm angle on gantry and I get 6000mmpm rapids easily 4000 cutting 2000mm with 6mm 2 flute 12mm DOC in MDF without breaking a sweat so I don't think you would be dissappointed at 48v. If your intending to weld together a steel replacement in near future then 70v might be worthwhile but can't see you could use the speed and power unless you build in steel.

[louieatienza]

Normally I'd recommend a larger PSU, which would necessitate more expensive drives. I think in this case with the high-lead screws, you're probably fine. Been running G540 with 48V and similar steppers on my router for some time now, just fine.

[fretman_2]

Thanks Gerry...the extra cost isn't a problem.

[fretman_2]

OK...the 48vdc power supplies aren't that expensive. Like Gerry said, I'll spend some extra $$ on drivers.

Normally I'd recommend a larger PSU, which would necessitate more expensive drives. I think in this case with the high-lead screws, you're probably fine. Been running G540 with 48V and similar steppers on my router for some time now, just fine.

[fretman_2]

My thoughts so far are to go with a 48vdc power supply and DQ542MA drivers that are rated at 50v. StepperOnline, where I purchased my motors, has a 500w 48v 10.4 amp power supply. Would that work in my situation with my 4 2.8A NEMA23's?

[Louis_Cannell]

4x2.8 =11.2 plus 2 = 13.2amp or about 635 watt minimum required really so you would be under rated, you could try one supply but the first time you drive 4 motors your under powered and pushing the supply past its limit. I had similar decision with my setup but 3 amp motors so went for 2 9.7 amp supplies to be certain.

[fretman_2]

I didn't think about using 2 power supplies. Thanks again Louis!

4x2.8 =11.2 plus 2 = 13.2amp or about 635 watt minimum required really so you would be under rated, you could try one supply but the first time you drive 4 motors your under powered and pushing the supply past its limit. I had similar decision with my setup but 3 amp motors so went for 2 9.7 amp supplies to be certain.

[Louis_Cannell]

I just wacked two drivers on each supply and a buck converter for driving water pump, fans, led lights etc so I can use some of the tons of 12v stuff I have laying around.

[ger21]

StepperOnline, where I purchased my motors, has a 500w 48v 10.4 amp power supply. Would that work in my situation with my 4 2.8A NEMA23's?

Yes, it will. Motors will not draw more than 2/3 of their rated current, so you only need about 8 amps for all four motors.

[fretman_2]

Got the lead screw bearing mounts cut out of HDPE and mocked up. Not thrust bearings, but good bearings and I can replace them easy enough. A little bit of lead screw whip, but I ran out of M5 bolts and wasn't able to fully bolt down the bearing mount. Hopefully the whip will go away.

[louieatienza]

Got the lead screw bearing mounts cut out of HDPE and mocked up. Not thrust bearings, but good bearings and I can replace them easy enough. A little bit of lead screw whip, but I ran out of M5 bolts and wasn't able to fully bolt down the bearing mount. Hopefully the whip will go away.

I used radial BBs on my large table and they work fine as long as you go light with preloading them.

[Louis_Cannell]

Only problem I can foresee may be the couplings, a trap I almost fell into, make sure motor spindles and screws have excellent locking to coupling additional weight and hopefully speeds load these couplings far more than I had originally considered. I ended up removing and machining mine after almost wrecking the gantry with my dual X screws when a coupling decided to slip during tuning & testing.

[fretman_2]

Doesn't seem like I'll be able to torque down that threaded collar enough to put too much tension on that lead screw.

I used radial BBs on my large table and they work fine as long as you go light with preloading them.

[fretman_2]

Yea...I worried a little about that coupler holding (even breaking) under torque. I think I'm going to got to a Lovejoy type coupler.

Only problem I can foresee may be the couplings, a trap I almost fell into, make sure motor spindles and screws have excellent locking to coupling additional weight and hopefully speeds load these couplings far more than I had originally considered. I ended up removing and machining mine after almost wrecking the gantry with my dual X screws when a coupling decided to slip during tuning & testing.

[fretman_2]

Well...I'm donating the Shapeoko2 to my local Makerspace this afternoon. I have to make room to assemble the new machine...it's do or die with the new machine.