In this paper, a novel algorithm is proposed to develop a 3D transient finite element model of multilayer laser solid freeform fabrication (LSFF) process. The proposed model predicts the clad geometry as a function of time and process parameters including laser power, traverse speed, powder jet geometry, and material properties. In the modeling strategy, the interaction between the laser beam and powder stream is assumed to be decoupled, therefore, the melt pool boundary on the moving substrate is obtained in the absence of the powder stream. Once the melt pool boundary is calculated, a deposited layer is formed based on the powder feed rate, elapsed time, and intersection of the melt pool and powder stream. After the deposition of each layer, the effect of this geometrical change into the thermal distribution within the model is considered for thermal analysis of the next layer deposition. In the numerical simulation, the effects of a non-planar surface on the process parameters such as powder efficiency and absorption factor are taken into account. Geometrical aspects of a thin wall of steel AISI 4340 with four layers are numerically simulated by the developed modeling strategy. Numerical results show that with the growth of the number of layers in the wall, the powder efficiency increases while the absorption factor decreases. Experimental and numerical results are compared to verify the accuracy and reliability of the proposed model.
Three dimensional finite element modeling of laser solid freeform fabrication of cobalt alloy stellite 21 with 1.5% nanoCeO2 on the low carbon steel 1015