High-Resolution Inherent Strain Method Using Actual Layer Thickness in Laser Powder Bed Fusion Additive Manufacturing with Experimental Validations

Abstract

Laser powder bed fusion (LPBF) additive manufacturing (AM) broadens the horizons of design in academia and industry. However, LPBF contends with challenges like residual stresses and distortions due to uneven heating and cooling, leading to substantial resource wastage. Accurately predicting residual stresses and distortions remains a hurdle, primarily due to the need for high-resolution modeling. In this study, a high-resolution model of the inherent strain method (ISM) with actual layer thickness for a cantilever geometry in LPBF is proposed for the first time. Experimental and numerical findings indicate that as the number of layers increases, distortions tend to decrease, while the residual stresses on the top surface consistently remain constant and close to the material’s yield stress. The model achieves good agreement (error of 7.1%) for deformation, while the prediction error of residual stresses is reduced from 69% to 32% compared to a traditional ISM model.

Keywords: Additive Manufacturing, Laser powder bed fusion, Inherent strain method, High resolution, Layer thickness, Parallel computing