Browsing by Author "Gerken, Julian Frederic"

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Open Access
Flow visualisation and evaluation studies on metalworking fluid applications in manufacturing processes : methods and results
(2023) Fritsching, Udo; Buss, Lizoel; Tonn, Teresa; Schumski, Lukas; Gakovi, Jurgen; Hatscher, Johnson David; Sölter, Jens; Avila, Kerstin; Karpuschewski, Bernhard; Gerken, Julian Frederic; Wolf, Tobias; Biermann, Dirk; Menze, Christian; Möhring, Hans-Christian; Tchoupe, Elio; Heidemanns, Lukas; Herrig, Tim; Klink, Andreas; Nabbout, Kaissar; Sommerfeld, Martin; Luther, Fabian; Schaarschmidt, Ingo; Schubert, Andreas; Richter, Markus
Metalworking operations rely on the successful application of metalworking fluids (MWFs) for effective and efficient operation. Processes such as grinding or drilling often require the use of MWFs for cooling, lubrication, and chip removal. Electrochemical machining processes require electrolyte flow to operate. However, in those machining operations, a fundamental understanding of the mode of action of MWF is lacking due to the unknown flow dynamics and its interaction with the material removal during the process. Important information on the behaviour of MWFs during machining can be obtained from specific experimental flow visualisation studies. In this paper, promising flow visualisation analysis techniques applied to exemplary machining processes (grinding, sawing, drilling, and electrochemical machining) are presented and discussed. Shadowgraph imaging and flow measurements, e.g., particle image velocimetry, allow the identification of typical flow and MWF operating regimes in the different machining processes. Based on the identification of these regimes, efficient machining parameters and MWF applications can be derived. In addition, detailed experimental analyses of MWFs provide essential data for the input and validation of model development and numerical simulations within the Priority Programme SPP 2231 FluSimPro.
Open Access
Fundamental characterization of lubrication effects through various cooling lubricants in the chip formation zone
(2025) Biermann, Dirk; Saelzer, Jannis; Bergmann, Benjamin; Schenzel, J.; Menze, Christian; Gerken, Julian Frederic; Wolf, T.; Denkena, Berend; Möhring, Hans-Christian; Zabel, Andreas
Using cooling lubricants in metalworking requires a high consumption of energy and resources. However, cooling lubricants serve to increase the productivity and quality of these processes. Accordingly, it is necessary to expand the efficiency of their application. This requires fundamental understanding of the working mechanisms. Driven by this motivation, this publication compares six cooling lubricants regarding their lubrication effect in orthogonal cutting. Three types of fluid supply, each conducted on a specific special machine tool for chip formation analysis, and two cutting speeds have been used in the tests. In order to analyze the lubricating effect of these different scenarios, force measurements were carried out and the chip formation was recorded with high-speed recordings. It was found that the process improvements due to lubrication is determined by the interaction of fluid properties, supply strategy and cutting speed. Moreover, clear limitations of water-based cooling lubricants (especially oil-water-emulsions) in the ability to lubricate the chip formation zone have been determined and quantified.
Open Access
Modeling and mitigation of vortex formation in ejector deep hole drilling with smoothed particle hydrodynamics
(2024) Baumann, Andreas; Gerken, Julian Frederic; Sollich, Daniel; Rupasinghe, Nuwan; Biermann, Dirk; Eberhard, Peter
Ejector deep hole drilling achieves high-quality boreholes in production processes. High feed rates are applied to ensure a high productivity level, requiring reliable chip removal from the cutting zone for a stable process. Therefore, a constant metalworking fluid flow under high volume flow rates or high pressure is required. Experimental results show a vortex formation at the outer cutting edge. This vortex can lead to delayed chip removal from the cutting zone, and ultimately, it can lead to chip clogging and result in drill breakage due to increased torque. This paper investigates modified drill head designs using the smoothed particle hydrodynamics method. The investigated modifications include various designs of the chip mouth covering. Besides graphical analysis based on flow visualizations, flow meters are placed at the tool’s head to evaluate the impact of the modifications on the flow rate and possible increased resistance and relocation of the fluid flow from the outer cutting edge to other parts of the tool. The simulation results for the reference design show the experimentally observed vortex formation, validating the simulation model. By adding the tool’s rotation in the SPH simulation, which is not included in the experiments for observation reasons, the vortex formation is positively influenced. In addition, some designs show promising results to further mitigate the vortex formation while maintaining a sufficient fluid flow around the cutting edges.