Product Code: ICA10_1601

Benefits from Combining Laser Beams with Different Wavelengths (Green and Ir) for Copper Welding
Authors:
Axel Hess, Institut Strahlwerkzeuge IFSW, University of Stuttgart; Stuttgart Germany
Andreas Heider, Institut Strahlwerkzeuge IFSW, University of Stuttgart; Stuttgart Germany
Rainer Schuster, Institut Strahlwerkzeuge IFSW, University of Stuttgart; Stuttgart Germany
Rudolf Weber, Institut Strahlwerkzeuge IFSW, University of Stuttgart; Stuttgart Germany
Thomas Graf, Institut Strahlwerkzeuge IFSW, University of Stuttgart; Stuttgart Germany
Presented at ICALEO 2010

Due to its very good electric and thermal conductivity, copper is a fundamental substance with a wide range of applications, which requires an efficient and reliable welding process with laser beams.
The low absorptivity of common laser beam sources in copper materials is a major challenge. Hence deep penetration welding is only possible with brilliant laser beam sources that provide high power and small focus diameters. Another way to achieve deep penetration welding is adapting the wavelength of the laser beam. For copper the absorptivity is increasing with a smaller wavelength and with a higher temperature of the copper material and also with a step during the phase transformation from solid to liquid.
Benefiting from these facts, a frequency doubled cw-thin-disk laser (515 nm) and a cw-thin-disk laser (1030 nm) are combined. The construction allows adjusting the relative positions of the two focal spots on the work piece.
Therefore a precursory green laser beam leads to a heating or even melting of the copper surface and the IR-beam interact with the preheated copper material with better conditions of absortivity. Thereby a more reliable process can be achieved in minimized time, especially at high welding velocities and short process times.