Grindability of additively manufactured Inconel 718

Additive manufacturing can produce complex shapes with minimum material waste. This advantage has made metal additive manufacturing attractive, and efforts are being made to make it more technically promising than conventional manufacturing processes. However, due to the layer-by-layer deposition, one of the main issues of the additively manufactured metal parts is the dimensional deviation and highly rough surfaces. This makes it difficult to use the parts in as-built condition and necessities post-processing to meet the required surface finish and tolerances. Hence, this study reports the underlying insights into the grinding of selective laser melting (SLM) printed Inconel 718. Experiments were conducted considering the wide range of equivalent chip thickness values and built directions of as-built workpieces. Specific grinding forces revealed the grindability of SLMprinted Inconel 718 with the number of passes and depth of cut compared to wrought Inconel 718. SEM images revealed the influence of the inherent pores on the metal additive manufactured samples in frequent abrasive grits fracturing and minor burn marks over the work surface, supported by the EDS analysis. The experiments conducted on porous structured samples also confirm the influence of pores on grit fracturing. The observed micro grit fracturing in SLM-printed as-built Inconel 718 mitigated the effect of strain-hardening on specific energy despite an increased hardness, unlike wrought Inconel 718.