Simple model for the laser powder interaction during direct metal deposition

Abstract

In this paper, a simple model is presented for simulating laser and powder interaction during a coaxial laser cladding process, which is a very important part of direct metal deposition. The powder is delivered coaxially with the laser. The idea is to completely melt the powder before it hits the substrate. The laser is being attenuated as it propagates through the cloud of powders. The laser beam that penetrated through the cloud is used to melt the substrate. The track of 3D printing is formed by resolidification as the laser or the substrate scans. The laser attenuation is modeled by the Beer–Lambert law. The heat transfer within each powder is modeled by a lumped capacitance method. We use an enthalpy formulation to easily model and track the melting. The resulting 1D differential equation is solved numerically using Euler's method. The enthalpy and temperature plot is presented. We make use this model to determine the standoff distance. The effects of powder velocity, laser power, powder number density, and powder radius on the standoff distance are investigated and presented.