Detection of Weld Defects by High Speed Imaging of the Vapor Plume

Using two high speed cameras, we analyzed the 3D vapor plume fluctuations during laser welding of steel sheets in overlap configuration. Our results indicate that the position of the vapor plume contains relevant information on the process state. Whereas an increase of the penetration depth shifts the plume position in negative welding direction, welding defects like spatter formation or holes in the weld seam cause strong fluctuations of the plume position laterally transverse to the welding direction.