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Department of Engineering, ICT and Technologies for Energy and Transport Patent Title Matrix and device and use thereof for optically- controlled release of chemicals. Ref. CNR 10139 Assignee (s): CNR CNR Institute: IFAC Main Inventor: Guido Toci Countries: USA Priority date: 31/08/2010 Abstract The invention relates to a method for the analysis of data generated by a spectroscopic sensor, which is used for measuring the optical emission of the plasma generated in the welding area, applicable for example to the welding process of pre-machined elements, such as print elements, slabs, elements obtained by casting. The method of analysis, by means of the examination in real time of the emission spectra acquired from said sensor, allows to identify the deviation of the physical parameters of the weld from a region of values considered as optimal; this deviation, if not controlled and corrected, can produce defects in the resulting weld. The information thus obtained can be used as input of a feedback system of the welding apparatus, which intervenes in real time on the physical parameters of the welding process, in order to correct the anomaly. Background The assembly by laser welding of semi-finished metallic elements is widely used in many industrial fields. Among the most popular laser technologies, there is the continuous laser welding realized with CO2 lasers. The control quality is often carried out at the end of the production process, with non-destructive methods (for example radiographic and ultrasonic control) or destructive ones (resistance tests, sections of the weld joint) on a limited number of samples. Technology The method relates to the on-line detection of the occurrence of weld defects during the manufacturing processes of metal sheets by means of a spectroscopic sensor that measures of the plasma emission spectrum in the melting point. In practice, the main defects of the welding process of interest are preliminarily parametrized by a 'learning‘ phase, and then they can be detected in real time. Advantages and Applications The patent offers significant applications in the automotive field for the control of the welding processes of car bodies, where the defect is currently verified on individual samples, with often invasive methods that require time-consuming operations, as well as a significant waste of materials, with consequent impact on production costs. Development stage The technique has been fully implemented and tested experimentally within a MIUR (Ministry of Education 23 and Research) project involving companies of the FIAT group.