What size Stepper motor for my CNC Wood Router

[The Gresley Luthier]

Hi all.

After many days of reading and researching, I may have made up my mind what Stepper Motors and Drivers to get for my self built CNC.

I have taken advice and picked NEMA 23's for all Axis & DM556T for all Drivers, my only concern now is which power should I choose, 1.8, 3.0 Nm bearing in mind I will mainly be cutting wood for my guitar bodies, sorry to be a pain, but I need to get this right first time due to cost restraints.

Also do I need Bi Polar or Unipolar, Hybrid, all very confusing.

Regards.

Ray.

[m_c]

I'd probably er on the higher torque side, and go for the 3.0Nm motors, certainly on the X and Y, as that's the axes that will be worked the hardest.
Z axis isn't usually worked quite as hard, so is usually more dependant on how heavy your Z-axis assembly is going to be, so the smaller motor may be good enough, although if you have the space, there wouldn't be any real downside to a larger motor.

Most modern steppers are technically Hybrid motors.
Bi Polar/Uni Polar depends on how they're wired, but for DM drivers you'll want them Bi Polar, and typically wired in parallel (that's if the motors are 8 wire. Some are only 4 wire so you don't get an option between parallel/series, and some are 6 wire for UniPolar/Series use only)

The key specification you want to look at, is the inductance figure. The lower the inductance figure, the better performing the motor is at speed.