Stepwise consolidation of metal powder by localized microwaves for additive manufacturing of 3D structures

This paper presents local solidification of metal powder, irradiated by localized microwaves, as potential means for stepwise additive formation of 3D structures. Experimental results of metal powder solidified locally by microwaves are presented in forms of spheres and rods in a 1-10 mm range. The feasibility of extending solid structures by adding powder batches and solidifying them locally, as building blocks, is demonstrated as the basic action for a stepwise additive construction. The experimental observations and numerical results suggest that the enhanced electric field between the metallic particles excite electric discharges (micro-plasmas) which initiate the magnetic heating process. The experimental results lead to the development of localized microwave technique for stepwise formation of metal structures, as a low-cost substitute for laser-based technologies for rapid prototyping (RP) and additive manufacturing (AM) systems in >1-mm³ resolution.