Investigations of Energy Density Effects on Forming Accuracy and Mechanical Properties of Inconel 718 Fabricated by LENS Process

The amount of heat input, expressed as energy density, is one of the key parameters for laser additive manufacturing process. It will affect the melt pool dynamics, such as melt pool/powder interaction and temperature distribution, during the material solidification process, thus exerting an important influence on the forming accuracy and properties of the fabricated part. This paper investigates the effect of energy density on the forming accuracy and physical/mechanical properties of Inconel 718 part fabricated by LENS technique. Specifically, geometrical accuracy and relative density are measured with thin wall specimens. Surface roughness test is performed with block specimens. Based on the experimental results of the forming accuracy, relative density, and surface roughness, the suggested energy density ranges from 83.33 J/mm2 to 137.5 J/mm2.