Applying optical coherence tomography for weld depth monitoring in remote laser welding of automotive battery tab connectors

This paper addresses in-process monitoring of weld penetration depth (WPD) during remote laser welding battery tab connectors using optical coherence tomography (OCT). The research aims at studying the impact process parameters on accuracy WPD measurements. In general, highest measurement is achievable by positioning OCT measuring beam toward bottom keyhole. However, finding and maintaining alignment between keyhole a challenging task because dynamic changes in size shape itself. above challenge (1) developing for Al-Cu thin foil lap joint (Al 1050 450 ?m Ni-plated Cu 300 ?m) novel adjustable ring mode (ARM) (2) integrating technology with two beams: one targeting another as reference to part surface (TwinTec technology). methodology underpinned “Keyhole Mapping” approach, which helps identify optimal placement considerations both stability Findings indicated that ARM results more stable process, reduces fluctuations opening, and, therefore, improve factor 50% (from average error 0.22 mm 0.11 mm). Results further identified feasible operating window beam, corresponding accuracy, below 20 length.