CO2激光焊接拼缝间隙缺陷的同轴实时监测

为了研究不同间隙下激光拼焊的焊缝质量及其对应的信号特征,采用自制同轴传感系统采集提取多种间隙下焊接时的同轴光信号,并对信号进行众数分析、分段功率谱分析和小波分析。结果表明,同轴光信号幅值的众数在不同间隙的焊缝段,聚集在线性可分的不同的区间,可以有效分开焊接质量不同的Ⅰ类、Ⅱ类、Ⅲ类焊缝;信号的分段功率谱分析能够较为直观地反映焊接状态的变化。同轴光信号小波分解后的第4层逼近信号,可以直观地识别出质量好的Ⅰ类焊缝。同轴光信号的第3层、第4层细节信号可以清晰地辨识出质量低劣的Ⅱ类焊缝。

Coaxial real-time monitoring of gap defect in CO2 laser welding process

In order to study the characteristic signals according to the quality of the welding with dissimilar gaps, the selfmade real-time monitoring system with coaxial sensors is applied to acquire and extract coaxial signal, and then the signals are analyzed with modes analysis, subsection power analysis and wavelet analysis. It is found that, the modes of coaxial optical emission of dissimilar gaps, clustering at distinct numerical range, can distinguish 1 st ,2nd and 3rd class welds of different welding quality effectively. The subsection power analysis of coaxial signals can reflect the welding changes obviously. The approximation signals on level 4 of the coaxial signals, after wavelet decomposing, can intuitionisticly distinguish the 1 st class welds, while detail signals on level 3 and level 4 of coaxial optical emission can clearly identify the 2nd class welds.