Why stepper motors? What about other types of motors?

Choosing an appropriate stepper motor such as nema size 17 can be difficult and time consuming. This webpage is intended to help you easily and quickly select a good stepper motor for your project. There is a lot to cover, so consider this the first part in the series.

Why stepper motors? What about other types of motors?
Stepper motors online are by far the most common types of motors used for CNC Machines. Stepper motors have a unique property that makes them particularly well suited for CNC motion. Each time a stepper motor receives a pulse, it only moves a certain amount. For a full step, this is usually 1.8 degrees and for a half-step this is usually 0.9 degrees. The reason this is important is because the computer running the motor doesn’t need to sense the actual position of the motor because the motor’s position can be calculated solely by how many pulses have been sent out.


Another possibility is to use PWM motors. These motors produce different torque depending on the duty cycle of a square wave signal it receives. However, a more complicated controller and an expensive quadrature encoder must be used to determine the current location of the motor at all times. This is a closed loop control system, where the system reacts based on position data which is detected through a sensor.