Abstract
In large-area electron beam (EB) irradiation method, metal surface can be uniformly melted by the large-area EB with the uniform energy density distribution of 60 mm in diameter. Therefore, highly efficient surface finishing of metal can be performed. Furthermore, when the EB is irradiated to the workpiece with convex part, the edge of convex part is rounded since material removal of edge is preferentially performed due to the difficulty of heat diffusion at the edge and the concentration of EB. Thus, it is highly expected that micro filleting at the edge of workpiece can be done by the phenomenon of preferential material removal of the edge of convex part. In this study, the possibility of micro filleting in large-area EB irradiation is experimentally investigated. Experimental results show that the curvature radius of edge increases with acceleration voltage of EB. However, resolidified layer thickness on the upper side surface of workpiece also becomes larger, and uniform resolidified layer cannot be obtained at high acceleration voltage. The micro filleting at the edge with uniform resolidified layer thickness and ideal curvature radius can be achieved by using large-area EB with low energy density and large number of irradiations.
