Tandem Nd:YAG laser welding Available to Purchase

A finite element model of the pulsed laser welding process has been developed. This model has been used to calculate the temperature at any point in the material being welded as a function of time. Consequently it may be used to predict the size and shape of weld zones, as well as estimate the cooling rates of the material. A series of experiments using a pulsed Nd:YAG laser has been performed on steel and aluminium, producing both spot welds and seam welds whose shape, size and microstructures have been examined and compared with what might be expected based on the output of the numerical model. It has been found that the model requires only one parameter to be adjusted to yield good agreement between experiment and theory. This parameter, the effective absorptivity, has a value of 25-35% for mild steel and 10-14% for aluminium. The study has been extended to investigate the effects of two laser beams, in tandem, on the welding process. Both experiment and theory show distinct changes in the size and shape of the weld zones as well as in the microstructures. These results have been used to interpret the influence various laser parameters have on this tandem welding process, and so determine the applicability of the technique.