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Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK
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PublicationNumerical chip formation analysis during high-pressure cooling in metal machining( 2024)
;Barth, Enrico ;Bock-Marbach, BenjaminMost metal turning processes utilize cutting fluids. Despite extensive experimental and analytical studies, the mechanisms of chip formation under consideration of a cutting fluid are still not entirely understood. Due to fluid-structure interaction, simulating wet cutting processes for an extended duration has not been feasible. The primary objective of this study is to utilize a simulation approach to provide additional information about the wet chip formation process in contrast to measurement methods, with a view to drawing conclusions. As methodology the Finite-Pointset-Method (FPM) is employed to simulate the chip formation process for dry, flood and specifically high-pressure cooling conditions during machining of carbon steel C45 as well as nickel-based alloy Inconel 718. Due to the increased relative velocity between workpiece and cutting fluid with the use of high-pressure cooling compared to flood cooling, numerical stability issues are present. Initially, the modeling approach to handle high-pressure cooling conditions is described and validated by an impact test. Subsequently the cutting simulation model is presented in detail and verified by measurements. The simulation results of stress, temperature and plastic strain rate fields are used to elucidate the observed discrepancies between various cutting fluid strategies in detail. These findings suggest explanations for the high efficiency of high-pressure cooling such as a decline of hydrostatic stresses or activation of ductile damaging. -
PublicationCooling Lubricant Boundary Conditions for wet Turning Simulations( 2023)
;Barth, Enrico ;Nabbout, Kaissar ;Sommerfeld, Martin ;Bock-Marbach, BenjaminDovgal, AndreyIn recent years, the rise in computation and modelling capabilities has enabled first chip formation simulations for wet cutting processes. Currently, chip formation simulations are limited to a small simulation domain around the cutting edge. Hence, vague assumptions of inflow boundary conditions of the cooling lubricant must be made. In this paper, a procedure is shown to determine the boundary conditions of the free fluid jet for different cooling lubricant strategies by combination of Particle Image Velocimetry (PIV) and meshfree fluid simulations. As a result, usual assumptions of cooling lubricant boundary conditions are evaluated and deviations are identified. -
PublicationCooling Capacity of Oil-in-Water Emulsion under wet Machining Conditions( 2023)
;Nabbout, Kaissar ;Sommerfeld, Martin ;Barth, Enrico ;Bock-Marbach, BenjaminMany industrial machining operations are carried out under wet machining conditions. Modelling and simulating fluid-structure-interactions and conjugate heat transfer are still a challenge nowadays. In this paper, temperature dependent heat transfer coefficients (HTC) h(T) are experimentally estimated for wet machining-like conditions in a jet cooling experiment. The transient temperature is thereby used to solve an Inverse Heat Transfer Problem for HTC function estimation. Determined HTC are applied as input in related jet cooling simulation using the Finite-Pointset-Method (FPM) to validate the modeling approach. Additionally, wet cutting simulations numerically highlight the influence of determined HTC h(T) on turning. -
PublicationHeat Transfer Study for Oil-in-Water Emulsion Jets Impinging onto hot Metal Surface( 2022)
;Nabbout, Kaissar ;Pasternak, Lars ;Sommerfeld, M. ;Bock-Marbach, Benjamin ;Barth, EnricoThe purpose of this work is to analyse numerically as well as experimentally liquid jets impinging at different angles (30°, 60° and 90°) and different velocities (4.7 m/s, 7.0 m/s and 9.7 m/s) onto a hot circular plate made of Inconel 718. Liquids used in the experiments are water and oil-in-water emulsion with 8% concentration of the mineral oil Adrana AY 401 from Houghton Deutschland GmbH. An infrared camera is used to measure the black-coated rear face of the plate during the jet cooling process. The temperature field obtained is then used as input to estimate the heat transfer coefficient. The heat transfer coefficient is estimated by solving an Inverse Heat Transfer Problem (IHTP). In addition, the transient growth of the wetting area is also shown for both liquids. The heat transfer coefficient obtained from the experiments are utilised as input in numerical simulations with the Finite-Pointset-Method (FPM). Comparison between experiments and simulations is done to validate the recently implemented evaporation modelling in the MESHFREE software. -
PublicationData for a simulation of metal cutting with cutting fluid using the Finite-Pointset-Method( 2021)
;Barth, Enrico ;Seifarth, Tobias ;Höchel, MaximilianEisenträger, AlmutThe measurement and simulation data, their preparation and the simulation setup published in this co-submission are related to the article ""Simulation of metal cutting with cutting fluid using the Finite-Pointset-Method"". Wet and dry turning experiments were conducted at the Institute for Machine Tools and Factory Management(IWF), Berlin, Germany. Required adaptions of the used software MESHFREE were performed at Fraunhofer ITWM, Kaiserslautern, Germany. Both institutes collaboratively developed and validated the orthogonal cutting simulation model using the Finite-Pointset-Method (FPM). In this paper all measurement and simulation data and their preparation methods are presented in detail. This includes the preparation methods of process forces, analysis of chip morphology images as well as measured contact lengths on tool rake faces. Moreover, the experimental and simulation data are provided at the Mendeley Data repository. Hence the reader can use the data for own validations and analysis. Furthermore, the used simulation model files are completely published at the Mendeley Data repository. It allows the reader to retrace all settings. In addition, this enables to repeat the simulations and to simulate other process parameter combinations according to own interests. -
PublicationFully coupled wet cylindrical turning simulation using the Finite-Pointset-Method( 2021)
;Barth, Enrico ;Quellhorst, Alexander ;Seifarth, Tobias ;Nabbout, KaissarSommerfeld, MartinIn industrial machining operations, many turning processes are carried out under wet conditions. In contrast, most simulation tools are only suitable for dry cutting processes due to challenges of modeling fluid-structure-interactions (FSI). In this paper, a wet, fully coupled cutting simulation using the Finite-Pointset-Method (FPM) is presented and validated for industrially relevant cylindrical turning. To facilitate the required reduction of the calculation effort, different routines like adaptive numerical discretization are applied. The results indicate different cutting fluid effects like evaporation areas around the chip.