Inspection of welding pool height from shading in pulsed GTAW with wire filler

Purpose – The control of weld penetration in gas tungsten‐arc welding (GTAW) is required for fully automated systems to overcome variations in the welding process. The surface depression of weld pool, or weld pool height, has a close relationship with width of the backside bead in the full‐penetrated weld. The purpose of this paper is to inspect the pool height. Design/methodology/approach – A fast linear approach, based on shape from shading (SFS) algorithm, was employed to reconstruct a 3D shape of welding pool from a 2D image, which was obtained from a real welding pool. Then the pool height can be extracted. Furthermore, three methods were introduced to improve the above algorithm. Findings – The reconstructed pool height was in good agreement with the real height of weld pool from experiments. Research limitations/implications – The algorithm requires a uniform reflection on the pool surface. Practical implications – This method is applicable to inspect weld pool height in GTAW. It is a basis for future work on control of weld penetration. Originality/value – A faster SFS algorithm has been introduced to extract weld pool height in real‐time. Moreover, the algorithm was improved to fit for extracting the surface shape of weld pool.