How to Control a Stepper Motor Using a Computer. Stepper motors produce accurate, computer-controlled motion for applications such as robotic arms and paper-feed mechanisms for printers.

Most 3D printers use stepper motors to control the movement of the extruder head. If you could actually print those motors it would be one more big step toward self-replicating hardware. Now ...

Due to this fine level of control, stepper motors are required in any applications where there needs to be an exact movement such as 3D printers and CNC machines (or robots).