The stepper motor itself does not have a self-locking function, but it can achieve self-locking function through external devices or control methods. Here is a common approach:
     1.Use threaded rod: Install a threaded rod on the stepper motor shaft and connect to the load through the nut. When the stepper motor stops rotating, the load will be subjected to the resistance of the threaded rod and maintain a fixed position to achieve self-locking function.
    2. Use brake device: A brake device can be installed on the stepper motor shaft, and when the stepper motor stops rotating, the brake device will automatically lock the shaft and prevent the movement of the load.
    3. Use closed-loop control system: By adding feedback devices such as encoders into the stepper motor system, closed-loop control can be achieved, monitoring the position of the load and applying appropriate feedback force when needed to achieve self-locking function.
    In general, to achieve the self-locking function of the stepper motor, it is usually necessary to combine mechanical design and control system design, and select the appropriate device or control mode to achieve the required function.