Additive manufacturing processes allow maximum geometrical freedom of design without forming tools, due to the layered structure of the components. Additive processes are ideally suited for the production of complex components that are primarily optimized for design and function. Access to industrial applications of additive processes requires a high degree of process and component reproducibility, reliable and designable processes and tailor-made component properties. The CRC 814 is operating in this field and concentrates on the processes of selective laser beam melting of plastics and metals as well as selective electron beam melting. The CRC 814 aims to produce multi-material components from plastics or metals with defined, reproducible and graded properties using powder- and beam-based additive manufacturing processes. This vision requires the analysis of the entire process chain, from powder production through processing to the final components. The simulation of the individual sub-processes on a micro-, meso- and macroscopic level enables the prediction of process behavior and component properties.

In the first funding period of the CRC 814, a basic understanding of powder- and beam-based additive manufacturing processes was created. The modification of the process for the realization of new component properties was the focus of the 2nd funding period. The numerical tools were improved in their efficiency in order to model first complete manufacturing processes and to enable the prediction of component properties in perspective. In the third funding period, the understood processes will be modified to produce components with reproducible, graded and defined properties. In addition, the material design during powder production is carried out with regard to the additive processes. The systematic derivation of correlations between powder, process, structure and the resulting part properties allows an improved process robustness to generate new component properties and multi-material parts. Furthermore, simulations will be qualified to predict the process behavior and component properties on micro- , meso- and macroscopic levels. The consolidation of the simulations implemented in CRC 814 into a virtual laboratory will enable an efficient, computer-aided design of material systems, process strategies and component properties in the future.

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The object of this sub-project is the scientific detection, the quantitative determination and the development of a fundamental understanding of essential material-related process variables, which explicitly describe the solidification behavior and the energy input during the laser melting process of polymers. The manufacturing of components with low internal stresses and high mechanical strength requires optimized process parameters which are derived from the process-oriented characterization of the powder materials with regard to their thermo-mechanical and optical properties.

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The goal of sub-project A6 is to generate graded part properties by local insertion of fillers and polymer blend powders by vibration nozzles in selective laser beam melting. In addition, methods for orientating fibers along z-direction to generate a higher strength will be implemented. In doing so, new degrees of freedom in setting part properties will be enabled. Thereby, the effects of locally inserted as well as oriented particles on process control will be the subject of research.

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Within sub-project B3, the basic influences of the process control of selective laser beam melting of polymers on the resulting part properties are analyzed. Therefore, the sub-processes powder coating, laser exposure and consolidation as well as the temperature control are scientifically investigated. Innovative process strategies, which fulfill the material specific requirements of semi-crystalline thermoplastics, are studied to produce parts with reproducible and defined properties.

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Aim of the project is the scientific development of a quality assurance system for polymer powders used in laser beam melting. The quality assurance system is based on two methods. First, an empirical model for ageing of polymers will be established, which considers beside chemical additionally physical ageing mechanism. The model is based on experimentally determined bulk material properties as well as rheological and thermal properties of the present material system. The material model in combination with process data allows the prediction of the ageing state and will lead to a demonstrator software, which will be experimentally validated. Furthermore, a measuring system will be developed, which allows for determination of powder flowability at elevated temperatures and rheological properties of the polymer melt. After validation, the quality assurance system will be transferred to a demonstrator system in close cooperation with the industry partner.

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The aim of the project is the systematic investigation of the process-geometry-interaction of thin-walled components for the production of locally adapted properties as well as the modeling of this effect in finite element simulations and structural optimization. In experimental tests, the main influencing factors are identified and mapped in relation to the building position in the process. New exposure technologies and strategies are used to manipulate the melting pool and homogenize component properties. The findings are incorporated into a wall thickness dependent material model for structural optimization, which is investigated in the project. The participating industrial partners will validate the results over the course of the project. The experimental findings and the wall thickness dependent material model will be used to develop a methodology for the product development of thin-walled structures. In the future, the product development process can be accelerated, and the economic efficiency increased. Based on these findings, new application areas for the selective laser beam melting of plastics can be opened up in the future.

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A new research training group at FAU is being funded by the German Research Foundation. The research training group entitled „Synthetic Molecular Communications Across Different Scales: From Theory to Experiments“, or SyMoCADS for short, is led by Prof. Robert Schober (as spokesperson) and Prof. Kathrin Castiglione (Chair of Bioprocess Engineering) as co-spokesperson.

This structured training program addresses the highly interdisciplinary field of molecular communication. Molecules are used as information carriers to communicate with objects, cells or organisms in environments that are not suitable for traditional communication systems based on electromagnetic waves. Three different work clusters involving researchers from the Departments of Electrical Engineering, Chemical and Bioengineering, Mechanical Engineering, Chemistry and Pharmacy and Biochemistry as well as the University Hospital are investigating the sensing and control of bioprocesses on a microliter scale, the control of magnetic nanoparticles in blood vessels and molecular communication via volatile odorous objects.

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