The electrode state is an important factor affecting the welding quality in the process of resistance spot welding, but there is still lack of an effective method to monitor the electrode wear state. In this paper, a novel online monitoring method of electrode wear state is proposed by exploring the variation pattern of dynamic resistance. The evaluation method of time series similarity is important for dynamic resistance data processing, and two types of evaluation methods including static evaluation method and dynamic evaluation method are proposed in this paper. The static evaluation methods include shape change factor, dynamic resistance decrease ratio and peak time delay, and the dynamic evaluation method refers to the trend change factor. The welding process parameters and the welding material are kept unchanged during the experiment, the newly polished electrode is used to weld 1300 times continuously, and dynamic resistance is collected. According to the results of data processing, the change of the electrode state can be divided into three stages: The electrode state is stable when the welding number is less than 360. When the welding number is in the range of 360–800, the electrode state is in the transition stage, and the electrode state rapidly deteriorates with the increase of the welding number. When the welding number is more than 800, the electrode state is completely deteriorated, and the electrode needs to be dressed. This study may pave the way for online monitoring of electrode wear state.

电极状态是影响电阻点焊过程中焊接质量的重要因素，但仍然缺乏监测电极磨损状态的有效方法。通过探索动态电阻的变化规律，提出了一种新的在线电极磨损状态在线监测方法。时间序列相似度的评价方法对于动态电阻数据处理具有重要意义，提出了静态评价方法和动态评价方法两类。静态评估方法包括形状变化因子，动态电阻减小率和峰值时间延迟，而动态评估方法是指趋势变化因子。实验过程中焊接工艺参数和焊接材料保持不变，新抛光的焊条用于连续焊接1300次，并收集了动态电阻。根据数据处理的结果，电极状态的变化可分为三个阶段：焊接次数小于360时电极状态稳定。焊接次数在360-800范围内时电极状态稳定。状态处于过渡阶段，并且电极状态随着焊接次数的增加而迅速劣化。当焊接次数大于800时，电极状态完全恶化，并且电极需要修整。这项研究可能为在线监测电极磨损状态铺平了道路。电极状态的变化可分为三个阶段：焊接次数小于360时电极状态稳定。焊接次数在360-800范围内时电极状态处于过渡阶段；随着焊接次数的增加，电极状态迅速恶化。当焊接次数大于800时，电极状态完全恶化，并且电极需要修整。这项研究可能为在线监测电极磨损状态铺平了道路。电极状态的变化可分为三个阶段：焊接次数小于360时电极状态稳定。焊接次数在360-800范围内时电极状态处于过渡阶段；随着焊接次数的增加，电极状态迅速恶化。当焊接次数大于800时，电极状态完全恶化，并且电极需要修整。这项研究可能为在线监测电极磨损状态铺平了道路。当焊接次数大于800时，电极状态完全劣化，并且电极需要修整。这项研究可能为在线监测电极磨损状态铺平了道路。当焊接次数大于800时，电极状态完全劣化，并且电极需要修整。这项研究可能为在线监测电极磨损状态铺平了道路。