Rule-Based Path Identification for Direct Energy Deposition

Abstract

Additive Manufacturing (AM) provides the possibility to produce complex part geometries on a layer-by-layer basis. In AM processes, a heat source moves over the part to either deposit powder or wire feedstock or to melt thin powder layers that are spread onto a powder bed. The moving heat source inevitably creates an inhomogeneous temperature distribution, which affects the residual stresses, part distortion, and local mechanical properties. Accumulation of heat in corners and path intersections may result in overheating and hence defects. In this study, a method for improving the temperature distribution in direct energy deposition processes is presented. FEM simulations in LS Dyna are coupled to MATLAB in order to divide a basic AM-FEM model and to adjust the model rule-based during the calculation. With this Rule-Based Path Identification (RBPI), the temperature history is used to choose the position of the next bead. With one bead wide wall, a temperature improvement of 90°C could be achieved. The new simulation method is adopted for a delay time between the beads for 10s. In conclusion, it is shown that the RBPD helps to reduce the inhomogeneous temperature distribution for a metal printing process without expensive optimization.