High-power disk laser welding statuses monitoring based on analyses of multiple-sensor signals

Welding statuses monitoring is crucial to quality control during high power disk laser welding of thick plates. A multiple-sensor-system is designed to capture the features of the keyhole, plume, spatter, optical and spectrum information of the welding area. These signals comprehensively depict the welding statuses, and are used to online monitor the welding statuses. The correlations between the captured multiple signals are analyzed by the correlation analysis method and Linear discriminative analysis (LDA) analysis and Stacked Auto-Encoder (SAE) are implemented, and the dimension-reduced non-linear transformation of the original features acquired by SAE shows better discriminative and representative capacity than the linear combination of the original features acquired by the LDA. This research not only investigates the correlations between the signals of the keyhole, plume, photodiode and spectrum information during high power disc laser welding but also provides a novel method to conduct online welding statuses monitoring. Three different welding experiments under different parameters were conducted, and these experiments include blowout, humping and undercut defects, respectively.