High power laser processes and on-line control

The research aims to understand the interplay between the laser beam, the material and the surrounding atmosphere during high power laser processes, with particular interest for welding, cutting and drilling with traditional as well as novel fiber laser sources. Development of optical sensors for real time monitoring and closed-loop control of laser processes is also addressed.

Laser welding and cutting are a crucial technologies enabling reduction of thermal distortions of the weld assemblies and enhancing productivity, but their application to ultra-high-strength steels, aluminum, magnesium and titanium alloys and composite materials is far from being a reliable technology. We investigate the physics underlying the laser material interaction, paying special attention to absorption of the beam in the material, heat conductivity, dynamics of gas shielding, melt, vapor and plasma, with the aim to enhance productivity, reliability and robustness of the laser processes. We also look towards the integration of laser welding, cutting, drilling and texturing technology into more complex manufacturing processes involving also cold, hot and superplastic forming.

The growth of the laser technology in the manufacturing industry goes together with the development of intelligent sensing techniques and control systems to ensure zero-fault production. Our research group develops real-time sensors and closed-loop feedback systems, based on the optical spectroscopy of laser-generated plasmas, to on-line monitor the occurrence of weld defects and/or control key quality issues of the laser welding processes like penetration depth and effective gas shielding .

Other research activities concern high-speed sensing and imaging with coherent illumination of the processing area to help determine geometric quantities and investigation of the laser process (welding, cutting) efficiency achievable with the new generation of high power and high brilliance fiber laser sources compared with traditional CO₂ lasers.