Stepper motors are widely used in servo control systems due to their precise positioning capabilities. However, the accuracy of their operation is a critical concern for engineers and designers. In open-loop systems, where no feedback is used, the motor’s performance depends largely on its internal design and the mechanical system it drives. While step angle accuracy is often emphasized, this may not be the most important factor in all applications. When a stepper motor operates without feedback, it relies on the interaction between the rotor and stator poles. Under load, the rotor can deviate from its ideal position, resulting in what is known as an offset angle. This misalignment can lead to angular loss, especially when the load torque changes or reverses direction. Understanding these effects is essential for optimizing the performance of stepping motor systems. Figure 1 illustrates the concept of the offset angle. When a load torque is applied, the rotor lags behind the stator’s magnetic field, creating a deviation that affects the overall movement. The magnitude of this deviation depends on the motor's torque characteristics, the energization pattern, and the load itself. For example, in systems with high load torque, the offset angle might be less significant than the actual angular loss caused by the load. Angular loss becomes more pronounced during direction changes. As the motor reverses, the rotor must overcome the previous offset before moving again. This results in a double loss of angle, which can accumulate over multiple steps and reduce overall accuracy. The impact of this phenomenon is particularly noticeable in precision applications such as CNC machines, where even small deviations can affect the final result. The relationship between the number of energization states and the amount of angular loss is also important. Higher resolution modes, such as microstepping, increase the number of steps per revolution but can also amplify the effect of misalignment. While microstepping improves smoothness, it does not eliminate the limitations of open-loop control. Therefore, careful consideration must be given to both the motor selection and the system design to ensure reliable performance. In conclusion, while microstepping technology offers benefits in terms of motion smoothness, its effectiveness in open-loop systems is limited by factors such as load torque and mechanical stiffness. Engineers must balance these considerations to achieve the desired level of precision and reliability in their applications. cnc machining aluminum parts Dongguan Yingxin Technology Co., Ltd. , https://www.dgyingxintech.com