Originally Posted by
Corvus corax
Servos really don't make sense until you get into high power requirements. I use 720 oz./in steppers, and with my ballscrews, they generate over 750Lb of linear force! Servos make sense if you are running continuous high speeds, or need more than 200 Watts of feed power, which is a LOT of force! Most CNC operations on hobbyist level machines run low speeds, with reasonably small actual cutting forces. Real high speed (like a commercial VMC), costs BIG money, and is largely unnecessary for most operations. Servos have their place, but generally cost more to implement than steppers. Closed loop stepper interfaces, like the ones offered by Rogers machine, pretty much eliminate the problem of lost steps, and ruined parts in Mach 2/3.
Steppers wont crash and burn themselves up like servos, as they are constant current devices, and simply stall when they jam up. Servos can continue to run, and the windings will turn to slag in short order if you haven't any current limiting on the drives. Steppers typically suit smaller machines.