Modeling of high-power cw Nd:YAG laser welding

The model developed allows us to know the temperature field in a cw Nd:YAG laser joining piece. To realize the model, a physical approach has been used for defining the heat sources. First, from a pressures balance the geometry of the keyhole is determined. Then, an analysis of the plume existing at the surface of the target shows that the beam is scattered by the plume and consequently one more heat source must be considered. The spectrometric characterization indicates that no ionized particles exist in the plume and certainly in the keyhole. So Fresnel absorption must be the predominant effects for energy absorption in the keyhole. This assumption has been verified owing to Fresnel absorption coefficient measurements.