激光-MIG复合焊接熔滴过渡对焊缝表面成形的影响  

Effect of Droplet Transition on Weld Surface Formation of Laser-MIG Hybrid Welding

作　　者：叶广文 刘倩雯 范西岸 张艳喜[1] 高向东[1] Ye Guangwen;Liu Qianwen;Fan Xi’an;Zhang Yanxi;Gao Xiangdong(Guangdong Provincial Welding Engineering Technology Research Center,School of Electromechanical Engineering,Guangdong University of Technology,Guangzhou,Guangdong 510006,China)

机构地区：[1]广东工业大学机电工程学院广东省焊接工程技术研究中心,广东广州510006

出　　处：《中国激光》2022年第8期121-133,共13页Chinese Journal of Lasers

基　　金：广州市科技计划资助项目(202002020068,202002030147)。

摘　　要：熔滴过渡特性对于保证激光-电弧复合焊接成形质量十分重要。利用高速摄像机采集激光-熔化极惰性气体保护焊(MIG)复合焊接过程中的熔滴过渡图像,通过图像信号处理方法提取电弧感兴趣区域(ROI区域)面积、熔滴速度、熔滴过渡周期等特征,分析熔滴过渡特征与焊缝成形的关联;利用短时傅里叶变换和谱熵对电弧ROI面积进行时频分析,研究功率谱谱熵与熔滴过渡稳定性之间的规律。结果表明:熔滴过渡频率与熔滴速度有一致的变化趋势,稳定的熔滴过渡能提高焊缝成形的均匀性;功率谱谱熵能表征焊接过程的稳定性,当熔滴过渡失稳时,短时对数功率谱变得紊乱,瞬时谱熵增大,焊缝熔宽减小,表面铺展性降低。Objective Several studies have been conducted on laser-MIG welding process monitoring technology because of the requirements of enterprises for higher quality output and traceability of products.Optical,acoustic,thermal,and visual signals were used to monitor the laser welding process.Moreover,optical sensors have been widely used to monitor various signals emitted by the laser as it interacts with the material,including visible light,ultraviolet light,infrared light,and laser reflection,which can effectively reflect the welding process state.Laser welding process monitoring based on optical signal has been widely used in 3C,new energy,automobile industry,and other fields.For laser-MIG hybrid welding,visual objects,such as keyhole,molten pool,vapor,and spatter,were not easy to extract due to the interference of the arc light.However,we observed a clear periodicity in the area of arc light that coincides with a droplet transition cycle.It was useful information to evaluate the state of droplet transition and welding process.The droplet transition features were analyzed in the time and frequency domains to investigate their influence on the process stability and weld formation.Methods Welding parameters,such as laser power,arc current,and voltage,were investigated using a single variable method.A high-speed camera was positioned horizontally on the side to capture the droplet transition image.The arc area was extracted by threshold segmentation,and the droplet contour was extracted using the Canny edge extraction algorithm.The barycenter of the droplet was calculated from the droplet contour.The velocity and position of the droplet that passed through a horizontal line were calculated from the barycenter of the droplet.The width and height of the weld were extracted using three-dimensional point cloud processing.Combined with the laser-arc interaction mechanism,the influence of laser power on the droplet velocity and trajectory,and the change in droplet trajectory during arc instability and its influence on the wel

关 键 词：激光技术 激光-电弧复合焊接 熔滴速度 熔滴过渡频率 稳定性 短时傅里叶变换 谱熵 

分 类 号：TG409[金属学及工艺—焊接]