Third Party Funds Group - Sub project
Mesoscopic simulation of the selective beam melting process

Project Details
Acronym: SFB 814 (B04)
Start date: 01/07/2011
End date: 30/06/2019

Abstract (technical / expert description):

The basic mechanisms that are essential in the powder based selective beam melting process are poorly understood. Most of the existing analytical and numerical models describing the process of consolidation in a homogenized image, i.e. individual powder particles are not resolved. This approach is suitable for information on averages, but cannot capture the local influence of the powder, i.e. the powder size distribution, the stochastic effect of the powder bed, the wetting of the powder by the melt and the formation of the melt. The actual selective melting process and thereby acting mechanisms can only be understood on the scale of the powder particles, with the help of numerical simulation on the mesoscopic scale. The aim of this project is to provide a numerical tool for mesoscopic simulation of selective beam melting and to use it to develop innovative process strategies. The mesoscopic scale allows the prediction of defects, surface quality and accuracy of the structure for different materials as a function of material parameters (powder form, bulk density, ...) and the process parameters (beam shape, energy per unit length, speed, ...).
In the first phase, a tool for the 2D simulation of selective electron beam melting was developed and validated with experimental results. The main task was the modeling of the entire build process with its different time scales (pre-heating, melting, applying new powder layer). Among other things, the complex coupling of the beam in the powder bed, radiation losses at the surface, mass and energy loss through evaporation and the deformation of the molten bath by the evaporation pressure is taken into account. The software is now able to simulate assembly processes, taking into account different scanning strategies on many layers. Such process strategies as the remelt strategy and the refill strategy are investigated. The verification of the numerical results is done in close cooperation with subproject B2.
In the second phase, the previous model is transferred to polymers. For this purpose, the absorption of the laser beam in the partially transparent stochastic powder bed and the highly viscous, viscoelastic material behavior must be described. Development and verification of the model is carried out in cooperation with subproject B3. In a further step, a method of 3D simulation of the grain structure in the selective beam melting of metals is implemented, in order to predict the texture of the materials as a function of process strategy.

Overall project details
Overall project: SFB 814: Additive Fertigung
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Last updated on 2017-06-30 at 16:44
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