An improved CSF model and an improved KGC technique incorporated in SPH for modeling selective laser melting process

Selective laser melting (SLM) is an advanced additive manufacturing technology related to the powder bed fusion (PBF) process. Numerical simulation is the key means of realizing the shape and property control of components for additive manufacturing. In this paper, an improved smoothed particle hydrodynamics (SPH) method is proposed for the numerical simulation of the SLM process, focusing on the melt pool flow. The accuracy of calculations at the free surface is significant for modeling the SLM process and there are kernel function truncation errors of the SPH method at the free surface. Therefore, an improved kernel gradient correction (KGC) technique and an improved continuous surface tension model are proposed to improve the accuracy of calculations at the free surface. The KGC technique can improve the accuracy of the kernel gradient in SPH approximation, however, the accuracy of KGC will decrease on the free surface. To improve the computational accuracy on the free surface, an improved KGC is developed. The surface tension model is significant for the numerical simulation of the SLM process, and an improved continuous surface tension (CSF) model is developed to enhance the stability and accuracy of surface tension modeling. In addition, a Gaussian heat source model and a latent heat model are introduced in the improved SPH model. The accuracy and effectiveness of the present SPH method for simulating the melting and melt pool flow of the SLM process are also verified by four numerical examples.