The effect of plasma-assisted machining and additive path strategies of Inconel 718 manufactured with directed energy deposition

Recently, Inconel 718 has been used as a key component in the automobile and aerospace industries because of its excellent strength and corrosion resistance, even in high-temperature environments. If Inconel 718 is manufactured using additive manufacturing (AM), it is possible to manufacture products at a low cost and time without a mold in the prototype stage. However, post-processing is essential for AM because of the limitation of the surface quality. Therefore, in this study, Inconel 718 was manufactured using directed energy deposition (DED) in AM, and plasma-assisted machining (PAM) was performed as a post-processing step for efficient machining. In addition, Inconel 718 workpieces were fabricated with three additive paths (X-, Y-, and cross-path) to analyze the effects of the additive path on the mechanical properties and microstructure during DED. Before performing PAM, the depth of cut was determined through thermal analysis of the plasma heat source. To analyze the machining effect of PAM, the cutting force, surface roughness, burr formation, hardness, and microstructure of the DED-formed Incoenl718 were compared with those of conventional machining. It was confirmed that PAM can be used for post-processing of AM parts because of its excellent machining effects.