Method for quality control of a welding joint between a pair of ends of conducting elements of an inductive winding of a stator

A method for quality control of a welding joint between a pair of ends of conducting elements of an inductive winding of a stator, said method being performed by a computer, comprising the steps of:

• acquiring a 3D reconstruction of said welding joint;
• extracting a white 2D grayscale blob area from said 3D reconstruction of said welding joint, by transversely sectioning said 3D reconstruction with a cutting plane that is arranged at a cutting distance from a peak of said 3D reconstruction, said cutting distance being chosen so that said cutting plane is further downward than a base of said welding joint, and assigning a white color to the area of said 3D reconstruction above said cutting plane in order to determine said 2D grayscale blob area;
• calculating a center of mass of said 2D grayscale blob area in order to determine a rotation axis orthogonal to said cutting plane and passing through said center of mass;
• extracting a plurality of profiles from said 3D reconstruction of said welding joint, by longitudinally sectioning said 3D reconstruction with a plurality of planes that are orthogonal to said cutting plane, proceeding in rotation about said rotation axis, each orthogonal plane comprising a respective profile of said 3D reconstruction;
• searching for and identifying bare zones of said welding joint by analyzing one by one profile portions of said plurality of profiles of said 3D reconstruction, calculating for each profile portion a respective straight interpolation line on points that constitute said profile portion, said profile portion being identified as a bare zone if said respective straight interpolation line has an angular coefficient with an absolute value smaller than or equal to 10°;
• and
• calculating a bare area of said welding joint by summing said bare zones identified by the analysis of said plurality of profiles of said 3D reconstruction, a contribution of each bare zone to said bare area being equal to an arc of an annulus comprised between said respective profile portion in which said bare zone has been identified and a following profile portion from the analysis of said plurality of profile portions.