Inherent Strain Analysis Using Experimental Multi-layer Model for Electron-Beam-Melted Parts

In additive manufacturing of metal products, predicting deformations induced during the process is indispensable for improving the quality of the products and reducing the post-process machining time. Finite element analysis (FEA) based on the inherent strain method using a voxel mesh is an effective prediction method due to its reasonable analysis time, and to efficiently implement the prediction, a method of easily and accurately defining the inherent strain value is required. In this study, an analysis method based on multi-layer model theory was proposed to evaluate the inherent strain applicable to electron beam melting. The inherent strains obtained by the analysis were - 0.835% and - 3.42% for 12Cr steel and Co alloy, respectively. As a verification result using the FEA based on the analyzed inherent strain, the out-of-plane deformation of the base plate and the thickness of the manufactured parts were evaluated with accuracies of ± 2.0mm and ± 0.5mm, respectively.