Selective electron beam melting (SEBM) is a powder-bed-based additive manufacturing (AM) technology to produce metallic parts of high geometric complexity. The non-contact melting by the electron beam under vacuum conditions facilitates the manufacturing of high-melting and reactive metals. Main applications are among others the aerospace, which benefits from significant weight losses by optimized part geometries, and the medical engineering, which depends on patient-customized biocompatible implants. Long process times raise high unit costs, which hamper expanding application fields, e.g., in the automobile industry. Process time reductions are expedited by the development of future SEBM machines equipped with more powerful electron beam guns. However, higher power intensities and build rates applied on state-of-the-art process strategies diminish the part quality and process stability mainly due to high evaporation rates. Therefore, modified process strategies need to be developed. Lacking knowledge about the exact interplay between the physical material behavior and process control encouraged the development of a two dimensional simulation software giving an insight into the interaction of electron beam, melt and powder bed. As a consequent advancement, a three dimensional simulation software on the basis of a source code for free surface fluid flows is developed in this work. The underlying isothermal lattice Boltzmann (LB) approach is extended to a thermal multi-distribution LB method including the development of a thermal free surface Neumann boundary condition and is coupled with a discrete element (DE) method to model the powder delivery during the SEBM process. A comparison of numerical results with analytical solutions and experiments verifies the successful simulation of the SEBM process. The analysis of a state-of-the-art process strategy reveals its upper limits of the build rate and power intensity, which do not exploit the possible capacities of future SEBM machines. Selective advancements of this ...
Numerical Modeling and Simulation of Selective Electron Beam Melting Using a Coupled Lattice Boltzmann and Discrete Element Method ; Numerische Modellierung und Simulation des selektiven Elektronenstrahlschmelzens basierend auf einer gekoppelten Gitter Boltzmann und Diskrete Element Methode
2015-01-01
Theses
Electronic Resource
English
DDC: | 629 |
Automotive engineering | 2006
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