Numerical investigation of the influence of laser beam mode on melt pool

During the laser material interaction process, the laser beam mode has significant influence on the formation and development of the melt pool, which directly affects the product quality. In the present study, a mathematical model and related numerical methods have been developed to simulate the process of laser material interaction for different laser beam modes. Three types of symmetric laser beam modes, TEM00, cylindrical TEM01* and TEM10 modes, and one nonsymmetrical rectangular TEM01 mode are considered. Since spatial distribution of the laser beam intensity varies with beam mode, the formation procedure and the shape of the melt pool in these four cases exhibit quite different features. Flow pattern, which is driven mainly by the thermo-capillary force and recoil pressure, together with temperature distribution are investigated and compared. Physical phenomena such as melting, solidification, vaporization and evolution of the free surface are incorporated in the present model.