Product Code: ICA12_604

Detection of Faults in Laser Beam Welds by Near-Infrared Camera Observation
Authors:
Friedhelm Dorsch, TRUMPF Werkzeugmaschinen GmbH & Co. KG; Ditzingen Germany
Holger Braun, TRUMPF Werkzeugmaschinen GmbH & Co. KG; Ditzingen Germany
Steffen Keler, TRUMPF Werkzeugmaschinen GmbH & Co. KG; Ditzingen Germany
Dieter Pfitzner, TRUMPF Werkzeugmaschinen GmbH & Co. KG; Ditzingen Germany
Volker Rominger, TRUMPF Laser- und Systemtechnik GmbH; Ditzingen Germany
Presented at ICALEO 2012

We monitor thin disk laser beam welding processes coaxially through the welding optics with a camera that is sensitive in the near-infrared spectrum (1000 to 1800 nm). With this sensor we detect the thermal radiation from the process zone and we can analyze the three regions laser spot, melt pool and heat-affected zone in real-time during the welding process. From the observed features we qualify the laser weld in respect to various welding faults. E.g. the weld pool geometry is correlated to full penetration, holes and spatters can be seen without additional illumination, and the thermal trace of the weld seam may qualify overlap joints and detect missing fusion. This in-situ online heat flow thermography is a unique method to detect false friends during the welding process itself.