Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    The potential of reducing the energy consumption for machining TiAl6V4 by using innovative metal cutting processes
    ( 2013)
    Uhlmann, E.
    ;
    Fürstmann, P.
    ;
    Rosenau, B.
    ;
    Gebhard, S.
    ;
    Gerstenberger, R.
    ;
    Müller, G.
    Two approaches for energy saving are presented in this paper for turning and milling TiAl6V4 workpieces. The major outcome of the cutting trials with the internally cooled turning tool is that the tool wear under dry cutting conditions is in between dry and wet machining, whereas the combination of the internally cooled turning tool with wet machining leads to strongly increased tool lifetimes. In contrast to this, the energy demand under dry cutting conditions is much lower than under wet cutting conditions. With respect to the environmental protection, the best tool cooling is dry cutting combined with the internally cooled tool. To achieve higher productivity rates or increased tool lifetimes, the combination of wet machining and the internally cooled turning tool is the best solution. In comparison to conventional milling, the average effective power consumption of the machine tool under trochoidal cutting conditions is increased by 6 %. Nevertheless, the amount of used energy is decreased by 15 % and the process time is reduced by 35 %. The reasons for this are higher material removal rates, due to the fact that the cutting time per edge and revolution can be reduced to a minimum. The heat-up phase and the cutting temperatures are small. By increasing the cutting parameters, e. g. cutting speed or feed, it is possible to improve the material removal rate. This enables a higher energy productivity and lower process time. The milling tool was used for both milling strategies. For trochoidal milling the tool has sufficient potential to increase the cutting parameters. For the conventional cutting process, however, the tool works at the load limit.
  • Publication
    Entwicklung der netzfreien Finite-Pointset-Methode für die Zerspansimulation
    ( 2011)
    Uhlmann, E.
    ;
    Gerstenberger, R.
    ;
    Schäfer, M.
    ;
    Kuhnert, J.
    Aktuelle Programme für die Finite-Elemente-Simulation von Zerspanprozessen verwenden Neuvernetzungsprozeduren, um die Trennung von Span und Grundwerkstoff abzubilden und die in den Scherzonen auftretenden großen Elementverzerrungen zu korrigieren. Diese Prozeduren schränken jedoch die Abbildungsgenauigkeit auf Grund von Interpolationsverlusten ein. Eine netzfreie Simulationsmethode ohne Neuvernetzungsprozeduren kann daher für die Zerspansimulation vorteilhaft sein. Im Rahmen der Weiterentwicklung der netzfreien Finite-Pointset-Methode (FPM) für die Zerspansimulation wurden ein Materialmodell für metallische Werkstoffe implementiert, Spanbildungssimulationen mit unterschiedlichen Werkstoffen durchgeführt und erste Schritte zur Darstellung des Kühlschmierstoffs in der Zerspansimulation unternommen.
  • Publication
    In situ experiments with synchrotron high-energy x-rays and neutrons
    ( 2011)
    Staron, P.
    ;
    Fischer, T.
    ;
    Lippmann, T.
    ;
    Stark, A.
    ;
    Daneshpour, S.
    ;
    Schnubel, D.
    ;
    Uhlmann, E.
    ;
    Gerstenberger, R.
    ;
    Camin, B.
    ;
    Reimers, W.
    ;
    Eidenberger, E.
    ;
    Clemens, H.
    ;
    Huber, N.
    ;
    Schreyer, A.
    High-energy X-rays offer the large penetration depths that are often required for determination of bulk properties in engineering materials research. Photon energies of 150 keV and more are available at synchrotron sources, depending on storage ring and insertion device. In addition, synchrotron sources can offer very high intensities on the sample even at these energies. They can be used not only to obtain high spatial resolution using very small beams, but also high time resolution in combination with a fast detector. This opens up possibilities for a wide range of in situ experiments. Typical examples that are already widely used are heating or tensile testing in the beam. However, there are also more challenging in situ experiments in the field of engineering materials research like e.g. dilatometry, differential scanning calorimetry, or cutting. Nevertheless, there are a number of applications where neutron techniques are still favorable and both probes, photons and neutrons, should be regarded as complementary. A number of in situ experiments were realized at the GKSS synchrotron and neutron beamlines and selected examples are presented in the following.
  • Publication
    In situ strain measurement in the chip formation zone during orthogonal cutting
    ( 2011)
    Uhlmann, E.
    ;
    Gerstenberger, R.
    ;
    Herter, S.
    ;
    Hoghé, T.
    ;
    Reimers, W.
    ;
    Camin, B.
    ;
    Martins, R.V.
    ;
    Schreyer, A.
    ;
    Fischer, T.
    The strain and stress state in the chip formation zone determines the chip formation. However, it is difficult to obtain experimental data about the strain/stress fields during machining. For this reason, present chip formation models highly simplify the chip formation process. In order to extend the knowledge regarding the chip formation mechanisms, an experimental method for the in situ measurement of the elastic deformations within the chip formation zone during the cutting process has been developed. Using these deformations, the stress state can subsequently be calculated. The method is based on X-ray diffraction using high-energy synchrotron X-radiation during machining the workpiece in an orthogonal cutting process under quasistatic experimental conditions. The diffraction patterns are captured with a 2D detector. A comparison of the experimentally determined stresses at different measuring positions within the chip formation zone with results from a FEM cutting simulation shows a good qualitative and partially also quantitative consistency. Possibilities for the further performance increase of the method are identified so that the method can be used for the verification and extension of existing chip formation models in future.
  • Publication
    Investigations on the adjustment of the modelling section in 2D simulations of milling processes
    ( 2009)
    Uhlmann, E.
    ;
    Mattes, A.
    ;
    Graf von der Schulenburg, M.
    ;
    Gerstenberger, R.
    Conducting 3D simulation of milling processes still causes high efforts. There, only small workpiece sections can be modelled so far, instead of the entire contact width. Approaches using 2D simulation pose an interesting alternative. Here, the two-dimensional perspective is gained by dividing the workpiece into different sections perpendicular to the feed rate. This, however, requires a modelling approach that covers arbitrary contact widths along with a high mesh density in the area of chip formation. Automatically adjusting the modelling section hereby helps to model contact width up to 180° by segmentally simulating the rotation of the milling cutter. This paper presents the investigations on the effect of the most important parameters which influence sufficiently accurate computation of the equivalent cutting forces as in conventional 2D simulation models using the software DEFORM 2D.
  • Publication
    Entwicklung leistungsfähiger Zerspanungstechnologien
    ( 2008)
    Uhlmann, E.
    ;
    Byrne, F.
    ;
    Oyanedel-Fuentes, J.A.
    ;
    Gerstenberger, R.
    ;
    Graf von der Schulenburg, M.
    ;
    König, J.
    ;
    Mattes, A.
    ;
    Richarz, S.
    ;
    Roeder, M.
    Der Beitrag stellt Aktivitätsfelder im Bereich der Zerspanungstechnik an einem von der Fraunhofer-Gesellschaft und der TU Berlin gemeinsam betriebenen Entwicklungszentrum vor. Kapitelüberschriften: neue Entwicklungen zur Zerspanung gehärteter Stähle; geometrische Modifikation von Diamant-Schneideinsätzen mit Laserstrahlen; Entwicklung und Einsatz superdünner Dünnschichtsysteme im Zerspanungswerkzeugen; Analyse der Zerspanbarkeit von partikelverstärkten Titanlegierungen; Modellierung von Größeneffekten bei der Zerspanung von Verbundwerkstoffen. Die Ausführungen werden durch Fotos von Anlagen und mikroskpischen Strukturen sowie durch tabellarische Ergebnisse ergänzt. Entnommen aus TEMA