[jfong]

NIC77,

Not really sure about the expansion capabilities of the different DUET boards. I’ll find out soon though.

I have a bunch of brushless drivers. Applied Motion, Copley, AMC, Baldor etc.

Some of them can be setup either trapezoidal or Sinusoidal commutation. From what I’ve read , sinusoidal is better so that’s what I choose. Better low speed performance.

You must be building a rather large 3D printer to require or want brushless servos. I was thinking of using brushless too on my printer build. Only because I have a bunch sitting around. I’m not in any hurry to finish it.

Jim.

[NIC 77]

Not really sure about the expansion capabilities of the different DUET boards. I’ll find out soon though.

Please post your findings when you do. I'd be looking forward to reading about it.

I have a bunch of brushless drivers. Applied Motion, Copley, AMC, Baldor etc.

Yes, I was looking at some EBay adds for Applied Motion drivers that specifically said "Sinusoidal" on them, whereas what I've read about the Leadshine ACS806 drivers leads me to believe that they are Trapezoidal, although I am not certain. I just know that it sends a trapezoidal signal when tuning the motors.

http://www.leadshine.com/UploadFile/Down/ACS806sm.pdf

There's lots of trapezoidal looking things in the above manual for the ACS806.

What set me thinking about it were a couple of threads I read on the forums:

https://www.cnczone.com/forums/diy-c...ry-router.html

https://www.cnczone.com/forums/bench...cnc-posts.html

https://www.cnczone.com/forums/bench...4-cnc-cad.html

All of the slides are driven by 4 pole 300 watt brushless Tamagawa servomotor. These require sinusoidal drive or they run very rough.

And it looks like I have the same motors he does.

Some of them can be setup either trapezoidal or Sinusoidal commutation. From what I’ve read , sinusoidal is better so that’s what I choose. Better low speed performance.

That's what I've read as well. The thing is, if I can't find appropriate drivers for a decent price then I may be better off spending the money on something like clearpath SD servos where the drivers are built in. Still kind of pricey, and it's a shame when I already have the brand new, unused Tamagawa Seiki's sitting there in front of me. I can get the Leadshine ACS806 for around $100 USD each. I may just go with some inexpensive Nema 23's. It's all still up in the air.

Also, it goes back to something you said in a previous thread, and I would be running them at 80V instead of 200V. The stages have a rated speed of 1200 mm/s but I would be very happy with 400mm/s.

I am considering running them at a lower voltage. The link below is an old thread some of this was discussed previously. I'm also looking to find a Kv rating for these servos, which is explained by jfong in post #11 in the thread below.

https://www.cnczone.com/forums/servo...33064-cnc.html

That's a quote from my thread here:

https://www.cnczone.com/forums/servo...-software.html

I'm a bit of an idiot when it comes to servo electronics, so as always, any advice is appreciated!

You must be building a rather large 3D printer to require or want brushless servos.

Yes, it's going to be a stupendous machine. Travels of 800mm (gantry) x (400mm to 600mm, I still haven't finalized the table design) x 600mm (Z). Dual lifting column, rising gantry (counterbalanced), moving table design. Also fully enclosed.

For the 3 stages I have already, size 25 NSK linear rails, with 4 bearing blocks and 2 rails on each stage, and ground 15mm OD ballscrews.

I figure that with two pellet extruders, if they each weigh 10 lbs or more, I'd still be more than fine to maintain whatever speed and accelerations the extruders could keep up with, having a very rigid machine.

The rising gantry moving table design keeps the moving parts relatively light for the constant X and Y accelerations of a 3d print that could take literally days to complete.

Plus it gives me a good base to turn the machine into a general purpose router / light duty aluminum mill, should I decide to do that instead, and I have a number of projects and potential mods I might do in the future.

ssashton, sorry for the hijack.