Real-time stereo vision for in-situ 3D reconstruction and realistic numerical simulation for GTA-WAAM

Most of existing 3D reconstruction techniques for wire arc additive manufacturing (WAAM) rely on laser scanning, which is associated with high costs and limited to offline operation. For complex components such as lattice structures, internal geometries cannot be scanned due to external occlusion, resulting in incomplete CAD models. To address this critical gap, we propose a real-time, cost-effective online reconstruction solution specifically developed for cylindrical rods fabricated via WAAM. The geometric morphology of the molten pool is defined as a hemispherical-capped cylinder. First, the 2D contour of the molten pool is segmented from images using morphological techniques. Then, the 3D coordinates of the molten pool’s centroid are calculated via stereo vision triangulation, and the 2D pixel coordinates of contour points are converted to 3D spatial coordinates using back-projection technology. Finally, spatial circle fitting is performed on the 3D contour points, and digital 3D model reconstruction is achieved through CAD lofting technology. Experimental results demonstrate strong geometric accuracy, with an average surface error of 0.31 mm and a volumetric intersection-over-union (IoU) of 0.87. Furthermore, the reconstructed 3D models enable realistic numerical simulations—validated by tensile tests where the simulated load–displacement curve aligns closely with experimental data.