The interpretation of sensor system data is critical for monitoring industrial welding processes and providing reliable information about the condition of the weld seam. Previous investigations have shown that acoustic emissions of frequencies up to several kilohertz during laser beam welding are parameter-dependent and contain valuable information about the process. A microphone was employed to record the acoustic emissions produced when performing deep penetration laser beam welding of copper. Experiments were conducted in which the laser power and the feed rate were varied so as to obtain acoustic data comprising frequencies of up to 1 MHz. The signals were preprocessed and features were extracted using Fourier and wavelet analysis as well as speech analysis techniques. The relationship between the features extracted from the acoustic signal and the weld depth was modeled using Gaussian process regression. The results showed that acoustic emissions during laser beam welding can be used to predict the weld depth without having to rely on process parameters, i.e., the laser power and the feed rate. Overall, 17 features were extracted from acoustic signals, with the zero-crossing rate displaying the highest significance for determining the weld depth. These investigations open up new possibilities of robust quality assurance for laser beam welding applications based on acoustic emissions.
In the publicly‐funded ProLasKu project, the laser manufacturer Trumpf has developed a high‐power laser with a wavelength of 515 nm. Substantial progress in the industrial applications of green lasers has been achieved in a cooperation between the Technical University of Munich and the companies Siemens and Continental. In addition, a camera‐based system for process monitoring and quality assurance in real‐time based on image processing methods has been developed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.