In a recently received article from AAC on the different merits between Servo's and Stepper motors in positioning control. " https://control.com/technical-articles/servo-motor-vs-stepper-motor-understanding-the-differences/ "I had a few issues with some of the claims.
I spent a good part of my career retro-fitting Industrial CNC machinery, and have never really come across any major CNC manuf. that uses steppers for motion control, it is usually left to the much smaller, less demanding systems manuf. or the DIY builder for small home use CNC tables etc.
I would refute the idea that Servo's cannot position to the same accuracy.
Servo's have higher RPM's, higher power, positioning precision and accuracy/resolution.
They maintain a high torque from zero RPM up to their maximum rated speed.
There are a few engineering papers out there that support the same view.
An extraction from a recent example :- .
"Servo systems provide the highest possible level of performance for precise control of position, velocity, and/or torque.
Compared to lower cost stepper motor systems, servo systems provide more torque at higher speeds, up to 5,000 rpm.
With stepper motors, the maximum torque is at zero speed, but servomotors have maximum torque at higher speeds.
Typical servo systems for machine control also provide a broader range of power, up to 3 kW or more, than stepper motors.
Perhaps the most notable difference between steppers and servomotors is that servomotors improve positioning with closed loop control.
Although some stepper packages take advantage of closed loop control, accurate and high-speed motion profiles without the motor stalling
and the related position error is a common advantage of servomotors.
Closed-loop position control, higher torque and higher speeds of the servomotor all confer benefits in high-accuracy applications."
I spent a good part of my career retro-fitting Industrial CNC machinery, and have never really come across any major CNC manuf. that uses steppers for motion control, it is usually left to the much smaller, less demanding systems manuf. or the DIY builder for small home use CNC tables etc.
I would refute the idea that Servo's cannot position to the same accuracy.
Servo's have higher RPM's, higher power, positioning precision and accuracy/resolution.
They maintain a high torque from zero RPM up to their maximum rated speed.
There are a few engineering papers out there that support the same view.
An extraction from a recent example :- .
"Servo systems provide the highest possible level of performance for precise control of position, velocity, and/or torque.
Compared to lower cost stepper motor systems, servo systems provide more torque at higher speeds, up to 5,000 rpm.
With stepper motors, the maximum torque is at zero speed, but servomotors have maximum torque at higher speeds.
Typical servo systems for machine control also provide a broader range of power, up to 3 kW or more, than stepper motors.
Perhaps the most notable difference between steppers and servomotors is that servomotors improve positioning with closed loop control.
Although some stepper packages take advantage of closed loop control, accurate and high-speed motion profiles without the motor stalling
and the related position error is a common advantage of servomotors.
Closed-loop position control, higher torque and higher speeds of the servomotor all confer benefits in high-accuracy applications."