Finite Element Thermal Analysis of Metal Parts Additively Manufactured via Selective Laser Melting

Abstract

In this chapter, a three-dimensional finite element model is developed to simulate the thermal behavior of the molten pool in selective laser melting (SLM) process. Laser-based additive manufacturing (AM) is a near net shape manufacturing process able to produce 3D objects. They are layer-wise built through selective melting of a metal powder bed. The necessary energy is provided by a laser source. The interaction between laser and material occurs within a few microseconds, hence the transient thermal behavior must be taken into account. A calibration procedure is carried out to fit the numerical solution with the experimental data. Once the calibration has corrected the thermal parameters, a dynamic mesh refinement is applied to reduce the computational cost. The scanning strategy adopted by the laser is simulated by a path simulator built using MatLab ® , while numerical analysis is carried out using ANSYS ® , a commercial finite element software. To improve the performance of the simulation, the two codes interact each other to solve the analysis. Temperature distribution and geometrical feature of the molten pool under different process conditions are investigated. Results from the FE analysis provide guidance for setting up the optimization of process parameters and develop a base for further residual stress analysis.

Selective laser melting finite element modeling: Validation with high-speed imaging and lack of fusion defects prediction

“…One key challenge is then to ensure that the model generates sufficiently accurate results in a limited amount of time, not exceeding the experimentation cost. Despite various attempts to simulate the process (as reviewed by [7], or more recently [8][9][10] for example), experimental validation of SLM models is indeed still an open issue that has been sparingly discussed in the recent literature. Many models have been validated employing post-experiment melt pool measurement by observing the metallographic cross-sections of the produced samples [11][12][13].…”

Part and supports optimization in metal powder bed additive manufacturing using simplified process simulation

“…Formula ( 1) is simple and very convenient to compute the total strain ϵ, since the key ingredient of the inherent strain method is to assume that ϵ * is known. In SLM many parameters affect the deformation of the part: of course the material properties, but also the machine parameters (power, speed and trajectory of the laser [12], [25], [26], [29]), acting directly on the heating and cooling behaviour of the part that cause the deformation. To find the inherent strain tensor ϵ * corresponding to a given set of machine parameters, one simple solution is to manufacture a test part, and match the deflection measured experimentally with the one obtained numerically with the right inherent strain tensor.…”

“…Differentiating L with respect to ûi gives the variational formulation of the adjoint problem (28). Assuming that the solutions v, u i are shape differentiable and differentiating L with respect to ω in the direction of the vector field θ, we obtain the desired shape derivative (29). Since Γ Ncut ⊂ Γ D and θ vanishes on Γ D , the integral on Γ Ncut in the Lagrangian (30) does not contribute to the shape derivative.…”

3D Printing of Integrated Metallic Reactor Catalysts: Concept and Application

“…Here the laser melting occurs along the outline (contour) of the structure, following a continuous path. Subsequently, the printer carries out the surface area exposure, running a hatch pattern over the larger bulk areas [34,35].…”