Product Code: ICA10_501

Ultra High Speed Camera Investigations of Laser Beam Welding
Authors:
Ingemar Eriksson, Luleå Univ of Techn; Lulea Sweden
John Powell, Luleå University of Technology; Luleå Sweden
Alexander Kaplan, Luleå Univ of Techn; Lulea
Presented at ICALEO 2010

With the help of high speed camera equipment, researchers can now directly observe melt flow phenomena which only could be imagined or simulated in the past. In this paper the motion of the molten metal inside the keyhole has been observed at frame rates as high as 180000 fps to provide useful information about the laser beam welding process. This paper describes two different cases where high speed imaging has given new insights into the laser beam welding process: a. In pulsed welding the melt pool oscillations can create ripples on the solidified weld surface. With the help of a high speed camera this phenomenon was analysed, and the pulse shape was adjusted to reduce the ripple amplitude to a minimum. b. In Zn-coated steel edge welding it could be seen that blowouts were sometimes created in the melt pool at some distance behind the keyhole. Direct slow-motion observation has led to the formulation of a phenomenological model of this effect.