Stepper motors move in fixed steps, are inexpensive and hold position well at low speeds, but lose torque as speed rises and can miss steps without feedback. Servo motors use encoder feedback in a closed loop, keep torque at high speed and correct errors, at a higher cost and with tuning. Closed-loop steppers sit in between.
Motion choices affect accuracy, speed and cost across a machine.
Compared
| Stepper | Closed-loop stepper | Servo | |
|---|---|---|---|
| Feedback | None | Encoder | Encoder |
| Torque at high speed | Drops | Drops | Maintained |
| Missed steps | Possible | Corrected | Corrected |
| Cost | Low | Medium | Higher |
| Tuning | Minimal | Minimal | Some |
| Typical uses | Low-speed positioning | Light automation | High-speed, high-load motion |
Choosing
- Required speed and acceleration.
- Load inertia.
- Positioning accuracy and need for feedback.
- Budget and controller compatibility.
Connect to the right PLC, compare AMRs and AGVs for material movement, and review belt-drive vs ball-screw linear units. Browse motion control.
For feedback and position retention, see the absolute vs incremental encoder chart.
Common questions
What is a closed-loop stepper?
A stepper with an encoder that detects and corrects missed steps, combining low cost with more reliability.
Do servos need tuning?
Usually some. Modern drives offer auto-tuning for most loads.
Which is better for CNC routers?
Hobby and light machines often use steppers; production machines usually use servos.