NEMA 17 closed loop stepper servo motors: These have frame size 42-42mm series , equipped with a 1000cpr incremental optical encoder, have great holding torque 0.45Nm, 0.59Nm and 0.75Nm. They offers higher accuracy, higher output torque, higher speed, lower motor heating, lower power consumption, and faster response to drive controllers compared to open loop stepper motors. Recommended drive: Leadshine CL42C Closed-Loop Stepper Motor Drive

NEMA 17 closed loop stepper servo motor Specification

• Step Angle: 1.8deg
  Bipolar/Unipolar: Bipolar
  Driving Voltage: 12-24VDC
  Frame Size: 42x42mm
  Shaft Diameter: Φ5mm
  Shaft Length: 24mm
  Encoder Type: Incremental Optical
  Encoder Resolution: 1000CPR
  42AI40EC-1000: 0.45Nm, 2.0A, total Length=60mm
  42AI48EC-1000: 0.59Nm, 2.0A, total Length=68mm
  42AI60EC-1000: 0.75Nm, 2.1A, total Length=80mm

A small tip:
Microstepping is a way to trick a stepper motor into moving smoother and with higher precision than it normally can. Normally, stepper motors move in discrete steps. Imagine a staircase – each step is a fixed size. A typical stepper motor might have a step angle of 1.8 degrees. So, with each electrical pulse it receives, the motor jumps 1.8 degrees.
This step-by-step movement can be jerky, especially at slow speeds. It’s not ideal for tasks that require smooth, precise control.