Sensor for the Detection of Protective Coating Traces on Boron Steel With Aluminium–Silicon Covering by Means of Laser-Induced Breakdown Spectroscopy and Support Vector Machines

Welding processes are one of the most widespread industrial activities, and their quality control, in both online and offline methods, is an important area of research. In the particular process of laser welding of boron steel with aluminium-silicon covering in the automotive industry, one problem is the presence of residual traces from the protective antioxidant coating, an aluminium-silicon alloy, which can result in a significant reduction of the welding seam strength. This work proposes a sensor system based on a laser induced breakdown spectroscopy (LIBS) setup to detect and discriminate aluminium residues in the welding area without destroying the sample before the welding procedure. A spectral algorithm based on support vector machines (SVMs) is used as a classifier to automatically identify areas with aluminum presence.