Macroscopic simulation and experimental measurement of melt pool characteristics in selective electron beam melting of Ti-6Al-4V

Abstract

Selective electron beam melting of Ti-6Al-4V is a promising additive manufacturing process to produce complex parts layer-by-layer additively. The quality and dimensional accuracy of the produced parts depend on various process parameters and their interactions. In the present contribution, the lifetime, width and depth of the pools of molten powder material are analyzed for different beam powers, scan speeds and line energies in experiments and simulations. In the experiments, thin-walled structures are built with an ARCAM AB A2 selective electron beam melting machine and for the simulations a thermal finite element simulation tool is used, which is developed by the authors to simulate the temperature distribution in the selective electron beam melting process. The experimental and numerical results are compared and a good agreement is observed. The lifetime of the melt pool increases linearly with the line energy, whereby the melt pool dimensions show a nonlinear relation with the line energy.

Modelling of additive manufacturing processes: a review and classification

“…In Table 6, a summarization of the process, parameters and KPIs of the different modelling approaches can be seen. In EBM, there is a limited number of the existing modelling publications, which focus almost entirely on thermal modelling [72], in which the analytical approach has been followed and [32,41,49,50,[73][74][75][76][77] via numerical methods. However, in [32] the residual stresses and distortions are also modelled using numerical methods.…”

“…Reference number KPI Process parameter (Variable) [32] Residual stresses, distortions [41] System temperature [49] Heat transfer related [50] Part Temperature history Layer position in the part under construction [72] Penetration depth, energy loss Target material, accelerating voltage [73] Absorption coefficient Penetration depth, dissipated energy [74] Thermal modelling, melt pool dimensions Beam power, beam scan speed [75] Thermal modelling, melt pool dimensions Beam speed, beam current, beam diameter [76] Thermal modelling Acceleration, voltage, current, shape, beam gun movements, exponential, constant absorption types [77] Thermal modelling, lifetime dimensions of the melt pool Scan speed, line energy Table 7. Classification of the of the modelling studies on the DED AM process.…”

Thermophysical Phenomena in Metal Additive Manufacturing by Selective Laser Melting: Fundamentals, Modeling, Simulation, and Experimentation

“…In [129], the pure thermal problem (8) has been solved for the EBM process based on the finite element method for spatial discretization and an implicit Runge-Kutta method for temporal discretization. Additionally, adaptive mesh refinement strategies have been applied in the direct vicinity of the electron beam.…”

Accurate Prediction of Melt Pool Shapes in Laser Powder Bed Fusion by the Non-Linear Temperature Equation Including Phase Changes

“…keyhole modes can neither be forecast nor replicated. This approach is well established in literature and has proven to be effective also in the thermal numerical analysis of large scale LPBF processes [5,7,20]. Other successful attempts in this direction, however with a focus on the scale of the melt pool, include the very recent publication of Zhang [26], which provides a summary of previous approaches but most importantly also incorporates anisotropic conductivities, as discussed in the paper at hand.…”