Surface Smoothing of AMed Metal Lattice Structures by Large-area EB Irradiation

In additive manufacturing (AM) processes, metal products with complex shape such as lattice structures can be produced by using 3D modeling data. However, the AMed metal products have large surface roughness, and surface irregularities such as spatter and cavities are also generated on the surface. They would lead to deterioration in mechanical properties for the metal lattice structures. The metal lattice structures have been smoothed by electrochemical polishing, but this method leads to low shape accuracy. On the other hand, metal surface can be melted instantly and uniformly by large-area electron beam (EB) irradiation, and surface smoothing can be performed. However, it has not been clarified that the AMed metal products with complex shapes such as metal lattice structures can be smoothed by the EB irradiation. In this study, possibility of surface smoothing for metal lattice structures by the EB irradiation was investigated. Experimental results show that almost whole connector surface of metal lattice structures can be smoothed by multi-step EB irradiation under magnetic field control with multiple yokes.