Numerical Analysis of Different Fixation Strategies in Direct Energy Deposition Processes

Production of components through forming requires extensive machining, high tool costs and long manufacturing times. Wire Arc Additive Manufacturing (WAAM), a direct energy deposition process, uses conventional arc welding technology to generate complex near net shape 3D parts. In Wire-Arc Additive Manufacturing (WAAM), a moving heat source melts the electrode wire and deposits the metal on the substrate. The movement of the heat source creates different heating and cooling patterns at different locations and causes distortions in the substrate and the part. This work presents a method to minimize the distortions and residual stresses of the substrate during the WAAM process. A three-dimensional finite element model has been developed using the software LS-DYNA. With numerical simulation, different fixation strategies of the substrate are compared according to the total distortion and the stresses. The results show that the fixation strategy of the substrate has a great influence on the distortion as well as the residual stress distribution. The influence of edge fixation strategy in minimizing the deformations is more than the corner fixation strategy. Among the edge fixation, the transversal edge fixation strategy has been found to have greater influence in enhancing the geometrical accuracy of the substrate by reducing the undesired stress distribution.