Product Code: ICA12_1709

Formation Mechanism of Process Instabilities and Strategies to Improve Welding Quality
Authors:
Volker Rominger, TRUMPF Laser- und Systemtechnik GmbH; Ditzingen Germany
Thomas Harrer, TRUMPF Laser- und Systemtechnik GmbH; Ditzingen Germany
Steffen Keler, TRUMPF Werkzeugmaschinen GmbH & Co. KG; -
Holger Braun, TRUMPF Werkzeugmaschinen GmbH & Co. KG; -
Friedhelm Dorsch, TRUMPF Werkzeugmaschinen GmbH & Co. KG; -
Felix Abt, Institute fuer Strahlwerkzeuge (IFSW); -
Michael Jarwitz, Institute fuer Strahlwerkzeuge (IFSW); -
Andreas Heider, Institute fuer Strahlwerkzeuge (IFSW); 0
Rudolf Weber, Institute fuer Strahlwerkzeuge (IFSW); --
Thomas Graf, Institute fuer Strahlwerkzeuge (IFSW); Stuttgart Germany
Presented at ICALEO 2012

The deep penetration process with CO2 lasers has been employed successfully for many years in industry. It generates little spatter on the work piece surface and therefore produces excellent seam quality at high process speed with good process reliability over a wide range of parameters.
With their wavelengths around 1 µm, solid-state lasers are being increasingly used in industrial production thanks to their simple beam guidance by means of laser light cable and their high electrical efficiency. Disk and fiber lasers have advanced into the domain of CO2 lasers by way of power and beam parameter product.
The seam quality is, however, highly dependent on the focusing conditions used, whereby the mechanisms that cause process instabilities are still not properly understood. Also, at high output densities with high feed rates, considerable spatter is generated on the work piece surface, reducing productivity in applications where the demands on surface quality are high.
In this publication, based on online X-Ray observation and high-speed imaging, the suitability for welding and the formation mechanism of process instabilities like spattering, dropping and humping of solid-state lasers and CO2 lasers were compared at different process parameters. Based on a better process understanding there will be strategies presented, which can improve the resulting welding quality.