Re: [CAD_CAM_EDM_DRO] Steppers vs Sevrvos?

Stephen Goldsmith wrote:

> Hello All,
>
> What are the +'s of Servos over Stepper motors and vice versa?

Ohhh, boy! Here we go again!

Steppers have discrete steps, clearly. A servo can move smoothly
through a set of arbitary points, not stopping at each one, unless the
motion is extremely slow. Microstepping increases smoothness of
motion, but doesn't increase resolution very much.

Steppers, when used without encoder feedback, can miss steps, such
that the machine is in a physically different position than the CNC
control wants it to be.

Servo systems cost more than steppers, although the difference is
getting smaller. At the least, you need to have a shaft encoder on the
machine, and possibly a tachometer, too.

Servos generally have more power than steppers of similar size and
(input) power rating. Steppers generally run hot even when standing
still. Servos rarely get warm to the touch.

Now that you've broken Pandora's box open again, the debate will rage
for weeks!

Jon