LASER-POWDER-MATERIAL INTERACTIONS IN THE LASER CLADDING PROCESS

In this paper we present briefly two possible approaches for modelling the laser cladding process. The first approach is 2D and consists in finding the shape of the molten pool given the fraction of the laser p ower which is available at the surface of the workpiece and given the amount of powder sticking to the molten pool. The powder reaching the workpiece is assumed to melt instantaneously at the surface of the mol ten pool, it is then mixed into the molten pool according to the compu ted velocity field. Because of its complexity, this model is solved on ly for two-dimensional situations and requires powerfull computers. On the other hand, accurate predictions of the shape of the molten pool are obtained. The second approach is 3D and takes into account the int erations between the laser beam, the powder particles travelling into the carrier gas and the molten pool. The laser power reaching the surf ace of the workpiece is estimated and, assuming this power is used to remelt the substrate with the clad being pre-deposited, the melt pool shape is computed using a 3D analytical model, which allows to obtain immediate results, even on personal computers. The predictions obtaine d with this numerical model are in good agreement with experimental re sults.