In digital motion control, the stepper motor is a particularly effective actuator, as it can faithfully execute commands given in digital form. This type of motor is currently widely used in the automation industry, especially the equipment that requires precise control. Stepper motors are widely used in machine tool such as CNC plasma cutting machine, wood machine, engraving machine, laser cutting machine ... In this report, we use 3D Printer for the example to stepper motor. Their downside is that their rotational accuracy is limited by the physical poles of the motor. This can be improved using micro-stepping. In summary, servos are great for some applications; but, for low cost situations like 3D printing, steppers are hard to beat. It is likely servos needed for milling CNCs because the cutting head is much more massive than an extruder or laser and the servo control loop is needed to provide accurate motion for the higher mass. From all reasons above, to build a 3D printer (especially in university, for a course project), Stepper motor is the best choice.