On the interaction mechanisms between a high-power diode laser source and silver alloys: The case of aesthetic welding

Welding process is generally considered as a crucial stage in the manufacturing of decorative items in silver alloys. It is mostly hand-made by using oxy-fuel torch and the final performance of the manufactured goods is too strongly related to the capability of skilled technicians and to the settings of factors often unpredictable. Further, spreading and out-of-control oxidative phenomena, troublesome reprocessing of the welded parts and unsafe operational conditions are determining a progressively growing demand for alternative welding technologies.The matter of the present investigation is therefore to evaluate the suitability of a high-power diode laser source in automatic butt-welding of sheets in ‘800/1000’ and ‘925/1000’ silver alloys. Interaction mechanisms between laser beam and underlying silver substrates in a chemical active environment were studied. A ‘first approximation’ oxidation model and, accordingly, simple tools for monitoring and control of the welding process was then proposed. Finally, butt-welding of thin silver sheets was successfully experimented.