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Simon C
29-03-2011, 08:00 PM
Anyone tried the digital stepper drivers from Zap automation 2M880N? Was wondering if they would give better speed and torque than the PM752 drivers?


Thanx in advance for any replys

regards
Simon

Gary
29-03-2011, 10:18 PM
What motor are you looking at using?
The PM752 is a good driver if used with Nema 23/24 motors, but is not a good option if used with Nema 34.

Simon C
30-03-2011, 11:07 AM
Gary,

I will probly be useing a mix of nema23 and nema34. Im going to convert a Amadeal AMA25LV mill to cnc http://www.amadeal.co.uk/acatalog/AMA25LV.html#a29 . So i was thinking mabe a 6Nm "ish" nema 32 on the Z axis, and two 4-5Nm "ish" nema 23s on the X and Y axis. Il be useing your ballscrews on all axis, thinking mabe 16mm Bscrews on X and Y and 16 or 20mm on the Z? Il be useing a direct 1:1 ratio bettween screw and motor. Would it be ok to mix diffrnt drivers on one machine? say 2 PM752s on X and Y runing the 2 nema 23s and 1 digital driver running the nema 34 for the Z? What kind of driver/motor setup would you recomend on this build? I heard that nema 34 size motors have a slower acceleration than the 23 size, is it true? and if so are they ALOT slower or is it hardley noticable?

Thanx for your replys

regards
Simon

Jonathan
30-03-2011, 04:48 PM
Nema 34 will have slower acceleration since it's rotor is bigger, causing the moment of inertia to be greater, but clearly the high voltage driver compensates.

Having different drivers on each axis is fine and a good idea to cut cost, potentially.

I think you'd be fine with Nema 23 (3 or 4nm) motors on X and Y. It's a similar size to my machine which runs well with 3nm and PM752.

If not already you should consider driving the ballscrews via pulleys/timing belts to get the most out of the motors.

Gary
30-03-2011, 07:29 PM
As said, higher inertia means they will not accelerate as fast, but you are converting a mill, so it is not as if you are going to be spinning then up to 1000 RPM anyway.
3Nm motors with 5mm lead ballscrews would be ok for the X and Y and a larger motor on the Z.
I have an X3 and this is a similar size, but i think my Z is heavier, i used 3Nm on the X and Y and an SY85STH80 on the Z with a 3:1 ratio for the Z and direct on the X and Y.
Gearing also increases resolution but at the same time means you need to spin the motor faster.

Simon C
31-03-2011, 04:27 PM
Thankyou both for your replys, think il probly copy the setup you used on your X3 gary, exept with mabe just a 1:2 ratio on the Z. I wont be starting this project just yet cos i still need to finish my router/plasma table build and minilathe conversion, alltho both are close to being finished.

regards
Simon