Evaluation for laser command generation in directed energy deposition applying a three dimensional heat conduction simulation

Metal additive manufacturing is a promising process for various industries in next generation, which provides high freedom of design, waste reduction, and applicability to difficult-to-cut materials. Directed energy deposition, which is one method of metal additive manufacturing, still has a challenge in the shape accuracy which deteriorates due to overheating in the edge. In order to suppress the overheating, this study proposes a laser command generation available to each deposition path by applying a heat conduction simulation. The laser command is determined by a three-dimensional heat conduction simulation with a finite difference method. The proposed laser command generation was evaluated through the deposition test, comparing with a conventional process with constant laser power. The experimental result clearly shows that the deformation due to overheating can be suppressed by adjusting the laser power according to the deposition height. Moreover, through the temperature measurement with a thermography, and calibrating the simulation, the deterioration in shape accuracy can be efficiently suppressed.