基于同轴视觉监测的激光深熔焊缝熔深监测

WELD PENETRATION MONITORING IN Nd: YAG LASER DEEP PENETRATION WELDING BASED ON COAXIAL VISUAL SENSING TECHNOLOGY

基于激光深熔焊接过程中稳态下小孔前壁材料气化满足的能量平衡以及在同轴视觉传感监测中提取出的小孔的径向尺寸建立了小孔深度的提取迭代方程,并基于小孔的深度实现了焊缝熔深的同轴视觉传感监测。试验结果表明：工件未焊透时,焊缝熔深的监测—计算值和试验测量值具有较好的一致性,其监测误差一般不超过12％；而工件完全焊透后,焊缝熔深的监测—计算值大于工件厚度,并基于此实现了工件是否焊透的判断。研究结果表明：基于同轴视觉传感和小孔前壁材料气化能量平衡建立的激光深熔焊缝熔深提取模型,可以有效实现激光深熔焊缝熔深的监测。

The iterative equation to extract the keyhole depth is founded according to the energy balance met by evaporation of the keyhole front wall and the extracted radial keyhole dimension in coaxial visual monitoring, and the weld penetration is monitored in the Nd： YAG laser deep penetration welding process based on the extracted keyhole depth. The studied resuits show that the monitored weld penetration accords well with that of experiment and the monitored error is less than 12% for partial penetration. While for full penetration, the monitored weld penetration is much greater than the thickness of the workpiece, which is used to judge whether the workpiece is fully penetrated or not. The experimental results indicate that it is effective to monitor weld penetration in laser deep penetration welding based on the energy balance model of keyhole front wall by using coaxial visual sensing system.