Characterization of Photodiodes for Detection of Variations in Part-to-Part Gap and Weld Penetration Depth During Remote Laser Welding of Copper-to-Steel Battery Tab Connectors

Abstract This paper addresses sensor characterization to detect variations in part-to-part gap and weld penetration depth using photodiode-based signals during remote laser welding (RLW) of battery tab connectors. Photodiode-based monitoring has been implemented largely for structural welds due its relatively low cost ease automation. However, research characterization, monitoring, diagnosis defects joining connectors is at an infancy results are inconclusive. Motivated by the high variability process dissimilar metallic thin foils, this aims characterize generated a determine whether quality can be isolated diagnosed. were collected RLW copper-to-steel thin-foil lap joint (Ni-plated copper 300 µm Ni-plated steel µm). The presented methodology based on evaluation energy intensity scatter level signals. gives information about amount radiation emitted process, associated with accumulated un-controlled variations. Findings indicated that diagnosed observing step-change plasma signal, no significant contribution given back-reflection. Results further suggested over-penetration corresponds increment Opportunities automatic isolation defective supervised machine learning discussed.