A CFD model of laser cladding: From deposition head to melt pool dynamics

The laser metal deposition process continues to receive attention from researchers and industry due to its unique capabilities in applications such as surface coating or rapid manufacture. The development of numerical models has proven useful for improving the process. However, most models have focused on analyzing individual stages of the deposition process and have required the introduction of a number of assumptions at their limits. This paper describes a complete CFD model that, starting from particles in the deposition head, simulates all interactions that govern the dynamics of a deposition melt pool. Individual phenomena that are included in the gasphase stage of the model include the ricocheting of particles within the head, the flow of powder particles, their interaction with the laser and powder catchment/bouncing. Phenomena in the liquid phase (melt pool) stage of the model include particle enthalpy effects, buoyancy, temperature-dependant material properties and Marangoni forces. The model is demonstrated using the actual geometry and gas flows found in a typical coaxial nozzle. The method, using a single technique to capture all phenomena, allows simulation of the melt pool dynamics from input parameters in a single model