DEM POWDER SPREADING AND SPH POWDER MELTING MODELS FOR ADDITIVE MANUFACTURING PROCESS SIMULATIONS

Particle-based numerical methods enable different process simulations for powder bed additive manufacturing. Two examples are the simulation of powder spreading and the simulation of melting and re-solidification. From these simulations, several material properties can be extracted such as packing density after spreading, porosity and surface properties after re-solidification and, ultimately, indicators for the strength of the component. In this work simulations of powder spreading using the Discrete Element Method (DEM) as well as simulations of the melt pool dynamics by means of Smoothed Particle Hydrodynamics (SPH) are presented. Surface tension material properties are varied and the influence on the resulting surface shape is discussed. The occurrence of different surface roughness patterns can be addressed to certain dimensionless numbers, namely the Capillary number, the Marangoni number and the ratio of the laser scan speed to a characteristic Marangoni current surface velocity.