Temperature-Based Trajectory Planning for Surfaces in Wire-Arc Additive Manufacturing

In Wire-Arc Additive Manufacturing, the desired workpiece is built layer-wise by a weld source moving freely over a substrate plate, either welding or transiting. The main issue with this manufacturing technique is the temperature distribution within the workpiece since the large thermal gradients caused by the welding process lead to thermal stress. We consider the trajectory planning problem of finding an optimal welding trajectory for a given two-dimensional layer. It is formulated as a mixed-integer linear problem (MILP) searching the welding path with the most homogeneous temperature distribution during manufacturing. The heat conduction, the weld source, and the heat radiation are incorporated into the model, together with two coupled time discretizations to accelerate the solution process. For two example surfaces, the computed optimal trajectory is compared to commonly used strategies like raster, zigzag or spiral paths.