Numerical simulations of melt pool dynamics in powder-bed additive manufacturing processes

Additive manufacturing processes currently penetrate both science and industry. These methods provide specific advantages including the customization and complexity of manufactured components. Additively manufactured components are already utilized in complex systems, for example airplanes. However, the reliability of these types of components is not yet satisfactory. At the moment, no established simulation tools exist for additive manufacturing. The availability of a continuous process simulation would be useful in view of the complexity of the processes to fulfill requirements for form and structure within the product development cycle. Particle-based numerical methods enable process simulations for additive manufacturing. These include simulating the spreading of powder yielding packing densities which influence the dynamics of the melting process as well as simulations of melting and resolidification which determine the porosity, the surface properties and finally the strength of the component. A simulation example is shown in the figure below. A loose powder packing obtained by a discrete element simulation provides the initial condition of the simulation. The melting and resolidification is then modelled using a smoothed particle hydrodynamics approach taking into account the interaction with the laser as well as melt pool dynamics including surface tension and Marangoni flows. The present study focuses on the modeling of different material and process parameters expressed as dimensionless numbers and their influence on the process result in terms of surface roughness.