A comprehensive review of extrusion-based additive manufacturing processes for rapid production of metallic and ceramic parts

The extrusion-based additive manufacturing (EAM) technique is recently being employed for rapid production of metals and ceramic components. This technique involves extruding the metal or ceramic material in solid powder form mixed with a binder (i.e., an expendable viscous fluid), which is removed from the part after 3D printing. These technologies rely on the large design freedom allowed and the cost efficiency advantage over alternative metal additive manufacturing processes that are based on high energy beams, such as laser or electron beams. The EAM of metals and ceramics is not yet widespread, but published scientific and technical literature on it is rapidly growing. However, this literature is still less extensive than that on the fused deposition modeling (FDM) of plastics or the selective laser melting (SLM) of metals. This paper aims at filling this gap. FDM and powder injection molding are identified as preceding or enabling technologies for EAM. This paper systematically reviews all aspects of the feedstock EAM processes used for production of complex-shaped parts. The unique characteristics and advantages of these processes are also discussed with respect to materials and process steps. In addition, the key process parameters are explained to illustrate the suitability of the EAM process for diverse application domains.