High speed video analysis of melt flow inside fiber laser welding keyholes

A high speed video survey of melt flow within fiber laser welding keyholes has revealed a number of interesting observations about the mechanics of weld formation. Using Streak Images and FFT (Fast Fourier Transform) techniques to interpret the video results, quantitative values of fluid flow velocities down the keyhole front have been established. The results have lead to a phenomenological understanding of some of the quality problems which arise at high welding speeds - such as undercut and humping.