Investigation of the Material Extrusion Additive Manufacturing of an Inconel-718 Filament

Material Extrusion Additive Manufacturing (MEAM) for metals is becoming increasingly appealing compared to other metal AM techniques, which are typically energy-intensive and require equipment expensive to install and maintain. In MEAM a polymeric feedstock filled with metal particles is extruded through a heated nozzle; subsequently, the 3D-printed green parts are debound and sintered. This study investigates the feasibility of producing functional Inconel-718 components with a commercial filament and a desktop printer, using a one-step thermal debiding and sintering procedure. To this purpose, the feedstock was extensively characterized, and optimal printing parameters were determined using the design of experiment technique and statistical analysis. Then tensile specimens were printed, debound, sintered and their mechanical and physical properties were measured. The specimens reached a maximum relative density of 83.4% and a maximum ultimate tensile strength of 223 MPa. A decrease in the debinding heat rate was required to avoid macro-void formation.