Fusing optical coherence tomography and photodiodes for diagnosis of weld features during remote laser welding of copper-to-aluminum
Fusing optical coherence tomography and photodiodes for diagnosis of weld features during remote laser welding of copper-to-aluminum
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DOI：
10.2351/7.0000803
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发表时间：
2023-02
影响因子：
2.1
通讯作者：
Tine Brežan;P. Franciosa;M. Jezeršek;D. Ceglarek
中科院分区：
文献类型：
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作者：
Tine Brežan;P. Franciosa;M. Jezeršek;D. Ceglarek
本研究旨在研究是否可以通过融合光电二极管和光学相干断层扫描 (OCT) 来隔离和诊断激光焊件特征的变化。在使用与 1D 振荡头集成的可调环模式激光器在 2 mm 厚的 Al 1050 板上远程激光焊接 0.2 mm 厚的铜箔时，考虑了两种制造场景（激光功率和焦距偏移的变化）。通过使用 OCT 测量焊缝熔深深度以及通过光电二极管进行过程发射（等离子体和背反射）来监控该过程。所有信号的采集频率均为 40 kHz。等离子体、背反射和 OCT 信号与测量的焊缝深度和宽度之间显示出很强的相关性 (r > 0.75)。观察到空隙、裂纹和传感器信号之间的弱相关性 (r < 0.5)。尽管等离子体是携带大部分工艺信息的主要信号，并且 OCT 允许直接测量熔深深度，但它们的集成在测试的焊接场景中达到了 87% 的分类精度。观察到的主要错误分类是根据测量的焊缝深度定义的“良好焊缝”和“过焊缝”。整篇论文讨论了具有制造意义的传感器融合策略。
This study has been designed to investigate whether variations in the features of laser weldments can be isolated and diagnosed by fusing photodiodes and optical coherence tomography (OCT). Two manufacturing scenarios (variation in laser power and focal offset) have been considered during remote laser welding of 0.2 mm thick Cu foils on 2 mm thick Al 1050 plates with an adjustable ring mode laser integrated with a 1D oscillation head. The process was monitored by measuring weld penetration depth with OCT and by process emissions (plasma and back-reflection) via photodiodes. The acquisition frequency of all signals was 40 kHz. Strong correlations (r > 0.75) were shown between plasma, back-reflection, and OCT signals and measured depth and width of the weld. Weak correlations (r < 0.5) between voids, cracks, and sensor signals were observed. Although plasma is the predominant signal that carries most of the information about the process, and the OCT allows direct measurement of the penetration depth, their integration reached 87% classification accuracy of the tested welding scenarios. The main misclassification was observed between “good weld” and “over weld,” defined by the measured weld depth. Sensor fusion strategies with manufacturing implications are discussed throughout the paper.