Diagnostic Methods Working Group
Prof. Dr. rer. nat. Joachim Mayer
Chair of Microstructure Analytics and Central Facility for Electron Microscopy (GFE)
The Diagnostic Methods working group focuses on the diagnosis and analysis of the molten mass, heat flow, and the temporal and local formation of the solidification process throughout the entire duration of the collaborative research center. The diagnosis of individual sub-process of the melting-based process is a prerequisite for quantitative modeling of the processes, dependant on the respective factors of influence, and provides a significant contribution to the comprehension and evaluation of processes and process parameters. In-situ methods, which not only depict the surface of a process but also the internal structure in and on the molten mass, are used to provide evidence about energy transfer, solidification dynamics, mixing, and the construction of internal tension. Work is completed in close collaboration with the Simulation working group, in order to mutually build on the respective results and ultimately, learn more.
High-speed Videography is considered a central tool to investigate the formation and movement of melt. Recording frequencies of up to one million images per second make it possible to analyze most dynamic movements of the melt and,
in combination with simulation models, to get an overall picture of melt dynamics. With the help of high-speed thermography, the model and the process description will be extended to address essential questions concerning transient energy transfer.
After a requirement analysis, the various devices available in the labs of the project partners will be made available to the processes that need them the most. A large part of the group’s activities focus on the development of method-specific lighting technologies which help to mask the respective process radiation fractions and thus make it possible to represent specific process details.
Large-Chamber Scanning Electron Microscopy
The working group “Large-Chamber REM” is concerned with the use of this unique high-resolution analytic tool for the purpose of providing a detailed description of melt processes with free surfaces. By means of temporary integration of e.g. laser beam sources into the large-chamber REM, movements and solidification processes can be registered that cannot be detected using conventional methods. Through the collaboration with partners from high-speed videography it becomes possible to achieve a high-resolution process representation for a number of melt-technological techniques.
Neutron Diffraction, Roentgen Analysis
The “Neutron Diffraction, Roentgen Analysis” working group is concerned with the volume analysis of molten phases and their impact on the development of mixtures and internal stresses within the component. It is planned to collaborate with TU Munich and Stuttgart University, a cooperation that provides access to high-resolution transmissive analytic tools that make it possible to determine the influence of energetic modulations on melt movement, energy transfer, and the dynamics within the melt. For welding, soldering, and coating processes, with the help of neutron diffraction methods, new insights into the inner structure of materials during the melt and solidification phases shall be gained.
Determination of Heat Transfer During Casting Processes
The working group “Determination of Heat Transfer During Casting Processes“ is concerned with investigating energy transfer processes in casting and injection molding tools. By means of a locally resolved measurement of thermal conditions using novel thermo sensors, the heat transfer from the solidifying component and the tool wall will be quantitatively determined. For plastics injection molding processes, which are thermally less demanding, transparent wall elements within the tool shall make the process optically accessible so that it can be captured using a thermo camera. In this way, temperature fields during and after the melt phase can be determined within the polymers at the wall, locally and temporally resolved. Thus insights into the heat development in the component can be gained.