同轴监测激光深熔焊熔池小孔的特征分析

为了研究激光焊接工艺参量以及焊接材料对熔池、小孔形貌的影响，搭建了激光焊接同轴监测系统，对比研究了有无辅助光源和不同工艺条件下、采用中心波长分别为532nm和808nm窄带滤光片同轴监测的熔池、小孔图像特征。结果表明，采用808nm激光辅助光源照明和808nm窄带滤光片，可清晰地拍摄到熔池、小孔以及穿透孔特征图像；相同的工艺条件下，熔池变化小，小孔动态波动且波动幅度小，穿透孔的时变动态特征较小孔则明显不同；熔池宽度随激光功率的增加而增大，随焊接速率增大而减小；不同材料激光焊接的熔池、小孔和穿透孔的同轴监测验证了本监测系统的稳定性。该研究对激光焊接质量实时监控有理论指导意义。

Feature analysis of coaxial monitoring of welding pool and keyhole during laser deep penetration welding

In order to study the influence of welding parameters and materials on the morphology of molten pool and keyhole, a coaxial monitoring system was built for fiber laser welding. The images of molten pool and keyhole were collected with 532nm and 808nm narrow band filter. Then, the 808nm laser illuminant was used to increase the light intensity of weld zone. The results indicate that, the detailed images of molten pool, keyhole and full penetration hole can be taken with 808nm narrow band filter under 808nm laser auxiliary illuminant. Under the same welding condition, molten pool and keyhole change in the stability, however, full penetration hole changes obviously with time. The change of weld pool is small. The change of small hole is dynamic and the fluctuation range is small. The dynamic characteristic of full penetration hole is obviously different from that of keyhole. The width of weld pool increases with the increase of laser power and decreases with the increase of welding speed. Coaxial monitoring of different material welding verifies the stability of monitoring system. This research provides theoretical instruction for real-time monitoring of laser welding.