The role of surface tension and wetting in the cultivation of metal products in direct laser 3D printing technologies

The three-dimensional convective heat and mass transfer occurring in a metal melt bath during layer build-up in 3D laser printing technologies (L-DED technology) is considered. The mathematical model of the considered non-isothermal hydrodynamic process with a phase transition is based on the Navier – Stokes, continuity and energy equations, taking into account diffusion, convective and radiative heat losses. The dynamic model of the free surface of the metal melt includes a Laplace pressure jump, Marangoni forces and wetting conditions. The numerical solution of the problem is performed by the method of mixed finite elements with a divergently stable approximation of the main variables. The influence of surface tension and wetting dynamics on the evolution of geometric parameters of a melt bath during thin wall growth is shown.