激光焊等离子体光电信号时域与自相关域分析

Time Domain and Autocorrelation Analysis of Optic-Electrical Signals of Plasma in Laser Welding

为了验证无源电探针检测装置对于等离子体电信号检测的有效性,基于等离子鞘层效应制作无源电探针检测装置,并利用高速摄像装置搭建了等离子体光电信号同步采集检测系统,在时域和自相关域内分别对A304不锈钢激光深熔焊过程中采集的等离子体电信号波形曲线和等离子体高度变化曲线对比分析,结果表明:等离子体光、电信号波动特征与波动周期基本一致,且波动周期为1.620～3.667,ms,利用高速摄像信号验证了无源电探针检测等离子体波动规律的有效性.

In order to verify the effectiveness of the passive electrical probe detection device in the detection of electrical signals of plasma.A passive electrical probe based on the principle of plasma sheaths and a high-speed CCD camera were used to detect the plasma electrical signals and record the plasma shape in A304 stainless steel YAG laser welding,respectively.The electrical signals and plasma plume height curves were analyzed in time and autocorrelation domains.The results show that the fluctuation characteristic and fluctuation period of electrical signal are consistent with those of optical signals,with their fluctuation period ranging from 1.620 ms to 3.667 ms.So,the high-speed camera signals are used to verify the validity of the passive probe for detecting the fluctuation of plasma.