Comparative investigation on grindability of Inconel 718 made by selective laser melting (SLM) and casting

Inconel 718 is increasingly manufactured by selective laser melting (SLM) for its excellent capability to shape complex parts. However, due to the limitation of current SLM process accuracy, for the parts with high accuracy and surface integrity requirements, subsequent process such as grinding is still necessary. SLM Inconel 718 possesses an anisotropic metallurgy microstructure that makes its grindability different from the conventionally made Inconel 718. Therefore, the grinding wheel wear and surface integrity of SLM Inconel 718 after grinding should be investigated for in-depth understanding of the correlation of SLM material property with its grindability. In this paper, inhomogeneous material properties and mechanical properties are characterized for SLM Inconel 718. Then, grinding experiments are conducted on both SLM and casting Inconel 718 for comparison. In order to investigate the effect of layer structure on the grindability and its variation trend in the whole grinding process, a step-traverse grinding mode is proposed to reserve the process status. Finally, the grinding wheel wear, power consumption, and surface integrity are measured for both samples. Furthermore, the correlation of the material properties with the grindability is analyzed, which will shed light on the process optimization for high-quality SLM Inconel 718 grinding for its reliable service in practical applications.