Thermo-mechanical modelling of the Directed Energy Deposition (DED) process for the optimization of deposition strategies

Directed Energy Distribution (DED) process involves in a continuous and subsequent deposition of layers by melting metal powders during which the influence of the DED process parameters set up (such laser power, powders flow rate, toolpath velocity) lead to different results in terms of distribution of the temperatures’ gradient and so residual stresses of the final printed component. For this reason, an investigation on the main process parameters influence on DED process has been done with a following tuning to suit them to the working case. Once the main process parameters were identified it has been pursued the main goal of this work: to analyze four scanning path strategies simulations of the component to be print, by highlighting the main differences between them in terms of deformation results. For this aim the 3DExperience software was fundamental and helpful to simulate correctly the DED process. A strictly algorithm has been followed to set up the various steps needed to prepare and run the various simulations: setting up the Finite Element Method (FEM) model, the type of mesh and its size, the material deposition conditions (heat source model, absorption, event series, …), the cooling settings (convection coefficient, emissivity). As final step once the best case in terms of deformations from the production perspective case has been highlighted, the component undergone post-processing machining to respect the designed dimensioning and tolerances. Future aims starting from this work can be achieved such as a deep study from metallurgic perspective view trying to reach as similar as possible the melting pool temperatures in simulation with respect to the experimental case. Also, a reverse engineering study can be led to get the desired designed component looking for to reduce at minimum the local deformations.