The following are common reasons.
1) Please confirm whether the pulse signal current of the controller is sufficient. Usually, the current should exceed 10mA to make the optocoupler work stably and transmit signals normally.
2) Please check whether the pulse of the pulse generator (controller) is too high and the stepper motor driver cannot receive the signal.
3) Confirm whether the starting frequency is too high, causing the acceleration time to be less than the acceleration ramp time of the drive, otherwise the motor may become unstable.
4) Please check whether the motor is fixed well. Otherwise, the motor will resonate violently, and then the stepping motor will loosen.
5) Please confirm whether the wiring of motor A and B is correct, and don't forget this step. Make sure that the connection between the stepper motor and the driver is firm.
6) Ensure that the driving voltage is normal. Choose a suitable driving voltage to ensure the voltage stability during the working time, so as to avoid jitter in the working process of the stepper motor.
7) Each stepping motor has a resonance area at low speed (sometimes other speed sections also have resonance areas). Avoid working in the resonance zone.
8) Ensure that the drive signal of the controller is stable and prevent unexpected signal loss.