Thermo-mechanical simulations for displacement prediction in Laser Direct Energy Deposition Wire

Laser Direct Energy Deposition with wire (L-DED-Wire) is an Additive Manufacturing (AM) process where the laser processing head and wire feeder are coupled with for example a 6-axis industrial robot to create 3D parts. Most laser wire welding systems have lateral material input instead of coaxial which is gaining popularity in additive manufacturing. Lateral material feeding works well in welding where the robot usually moves in one direction which is rarely the case in AM. The nature of layered material deposition causes various difficulties in the process and metallurgy such as changes in the bead geometry and displacement of the layers due to cooling. This can cause failures in the process and makes automating the process difficult without some kind of closed loop sensoring for position adjustment. This study investigates the use of thermo-mechanical simulation to assess part deformations during the L-DED-WIRE process and its impact on the process stability and print quality. Results may be used to help predicting possible points of failure and help the process planning to mitigate problems. Experiments are done with a laser welding robot with wire material Megafil 1100M. Simulation of the process is run using the same process parameters. Displacements after the process are compared with the simulation results. Simulations predicted well the rough displacement behaviour of the part but is limited in predictions of meltpool shape on bead geometry.