摘要
激光深熔焊接在航空航天、新能源汽车等精密连接领域中得到了广泛应用。然而,以铝、铜为代表的高反合金与高能量激光束的光-热能量转换易导致熔深不一致和焊缝缺陷,亟需实时监测与质量控制手段。光学相干层析成像(OCT)技术具有超高时空分辨率和不易受光辐射干扰的特点,能够实时准确地获取匙孔深度信息,但在实际测量过程中仍然存在一些误差,导致熔深精度不高。针对不同工艺参数下的高反合金点环激光焊接场景,提出了一种新颖的基于数据有效性判定的OCT熔深数据优化算法,主要包括信号降噪、重影消除、数据拟合、数据修正四个步骤。优化算法和实际焊缝熔深的对比结果显示,提出的优化算法适用于不同高反合金的激光焊接熔深监测,显著降低了熔深测量误差(低于6%),提高了熔深监测的准确性和处理效率,为激光工艺参数调控和焊接质量优化控制提供了可靠的解决方案。
Objective Laser deep penetration welding(LDPW)of highreflectivity alloys presents significant challenges due to the complex interaction between laser and material.Traditional methods for monitoring weld penetration depth are often inefficient or lack realtime accuracy,leading to inconsistent welding quality.Optical coherence tomography(OCT)has emerged as a promising technique for nondestructive,realtime monitoring of weld depth.However,the effectiveness of OCTbased penetration depth monitoring heavily depends on algorithmic optimization.This study aims to develop an improved penetration depth monitoring algorithm tailored for OCT,enhancing its accuracy and robustness when applied to highreflectivity alloy welding.By optimizing signal processing and feature extraction,this research seeks to advance realtime penetration depth measurement,contributing to more precise and efficient laser welding processes.Methods This study proposes an improved OCT weld penetration depth extraction algorithm,which optimizes the existing OCT measurement method through four key steps of“noise reduction‒ghosting elimination‒data fitting‒depth correction.”First,background noise from the charge coupled device(CCD)camera is removed using brightness distribution analysis,where a threshold is set to retain only valid data points.Second,the local outlier factor(LOF)algorithm is employed to detect and eliminate optical ghosting effects by analyzing density variations,and the primary data region is identified using a depthbased segmentation approach.Third,a moving average filter is applied to the keyhole depth data to smooth measurement fluctuations and obtain a continuous depth curve.Finally,based on metallographic measurements,a multivariate regression model is established to analyze the influence of welding parameters(laser power,welding speed,defocus amount,etc.)on the correlation between keyhole depth and actual weld penetration depth.This model is used to correct OCT measurement errors.The optimized algorithm significantly improves the accuracy and reliability of OCTbased penetration depth monitoring,providing a more robust method for realtime welding depth measurement.Results and Discussions The proposed optimization algorithm effectively improves the accuracy of weld penetration depth measurement based on OCT.By integrating signal denoising,ghost image elimination,curve fitting,and penetration depth correction,the algorithm significantly enhances the reliability of depth estimation under various welding conditions.The results show that the optimized measurement data closely align with actual metallographic depths,with relatively small error,confirming its feasibility for online monitoring.Moreover,the algorithm performs well in both linear and oscillating welding processes,demonstrating adaptability to different materials and welding parameters.These verification results further validate the robustness and high precision of the algorithm,making it a viable solution for accurately measuring weld penetration depth in industrial applications.Conclusions This study addresses the challenge of low penetration depth measurement accuracy in laser deep penetration welding of highly reflective aluminum and copper alloys.An optimized OCTbased algorithm,incorporating signal denoising,ghosting elimination,data fitting,and depth correction,significantly enhances measurement precision by mitigating noise and ghosting interference.Validation results demonstrate that the optimized algorithm improves accuracy across different materials and welding parameters,maintaining error within 6%,making it a reliable approach for realtime weld quality monitoring and closedloop control.
作者
任元昊
吴頔
侯泽恺
张路
刘源
董金枋
张培磊
Ren Yuanhao;Wu Di;Hou Zekai;Zhang Lu;Liu Yuan;Dong Jinfang;Zhang Peilei(School of Materials Science and Engineering,Shanghai University of Engineering Science,Shanghai 201620,China;Shanghai Collaborative Innovation Center of Advanced Laser Manufacturing Technology,Shanghai 201620,China;TRUMPF(China)Co.,Ltd.,Taicang 215400,Jiangsu,China)
出处
《中国激光》
北大核心
2025年第12期28-35,共8页
Chinese Journal of Lasers
基金
国家自然科学基金(52075317)
上海市自然科学基金(24ZR1427100)。
关键词
激光焊接
高反合金
光学相干层析成像
熔深监测
算法优化
laser welding
highreflectivity alloys
optical coherence tomography
penetration depth monitoring
algorithm optimization
