Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Micro-texture dependent temperature distribution of CVD diamond thick film cutting tools during turning of Ti-6Al-4V
    ( 2022)
    Uhlmann, Eckart
    ;
    Schröter, D.
    ;
    Gärtner, Eric
    Machining titanium alloys such as Ti-6Al-4V results in a high thermomechanical load on cutting tools and consequently short tool lifes. With respect to a necessary reduction of the resulting cutting tool temperatures, ultrashort pulse (USP) laser fabricated micro-textured rake faces offer direct supply of cooling lubricant into the cutting zone and lead to a reduced heat induction. As a result, micro-textured CVD diamond thick film cutting tools are also capable of machining high-performance materials due to reduced contact temperatures. In the scope of the research, the resulting temperature distribution for micro-textured rake faces will be compared under both dry and wet process conditions. Measurements show a reduction of the resulting cutting tool temperatures of Δϑt = 27.9 % using micro-textured cutting tools compared to non-textured cutting tools. A validated simulation provides valuable information about the contact temperatures enabling a specific development of the micro-texture geometry. As a result, a reduction of the contact temperature between chip and rake face by ΔϑT = 24.7 % was possible.
  • Publication
    Prediction of temperature distribution in diamond cutting tools during machining Ti-6Al-4V
    ( 2021)
    Uhlmann, Eckart
    ;
    Schröter, D.
    ;
    Wohlfahrt, V. H.
    The high thermal conductivity and wear resistance of CVD diamond provide potential for the machining of Ti-6Al-4V. By predicting thermomechanical loads, simulations can provide information about the usability of these cutting materials. However, the occurring shear chip formation within the cutting process leads to unsteady contact conditions. Therefore, a computationally intensive long-term transient simulation is necessary for precise prediction of tool temperatures. In this respect, a user-subroutine has been developed, allowing a high-resolution long-term simulation with acceptable computing time. By experimental investigations and validation of simulated results, a modelling of temperature distribution within the cutting tool is possible, providing valuable information regarding the contact temperatures.
  • Publication
    Case study for welding simulation in the automotive industry
    ( 2011)
    Perret, W.
    ;
    Thater, R.
    ;
    Alber, U.
    ;
    Schwenk, C.
    ;
    Rethmeier, M.
    Welding is one of the most widely used joining processes in structural applications, like in car body production in the automotive industry. It is well-known that distortions and residual stresses occur during and after the welding process. Many procedures exist to decrease these negative heat effects of welding, but are often coupled with highly cost intensive experiments. For several decades, simulation models have been developed to understand and predict the heat effects of welding and to reduce experimental effort. In the production planning of various Original Equipment Manufacturers (OEM), some simulation tools are already well established, e.g. for crash test, forming or casting simulations. For welding, the demand is high but the implementation of welding simulation software is sti ll not established yet. Welding is a complex process and the development of a flexible simulation tool, which produces good simulation results without expert knowledge in simulation, is not an easy task. In this paper, a welded assembly from the automotive industry has been simulated and compared to experimental data. Temperature fields and transient distortion distributions have been measured with thermocouples and with an optical 3D deformations analysis tool, respectively. The simulation has been run with a commercially available welding simulation software. The simulated temperature fields match the numerical ones perfectly. The simulated distortions are also qualitatively in best agreement with the experimental ones. Quantitatively, a difference of approximately 20 % between the simul ated and the measured distortions is visible; this is acceptable considering the simplifications and assumptions of the simulation model. The global time to solution to get these results without expert knowledge in welding simulation was between 4 and 6 weeks, which is a reasonable time frame for an industrial application of welding simulation.
  • Publication
    Microstructural changes induced by grinding of Ni-base superalloy IN 738 LC and their relationship to machining parameters
    ( 1994)
    Österle, W.
    ;
    Li, P.
    ;
    Niewelt, P.
    Die durch Schleifen der Nickelbasis-Legierung Inconel 738 LC erzeugten Gefügeänderungen wurden nach der Herstellung geeigneter Querschnittspräparate im TEM untersucht. Prinzipiell werden zwei Arten von Randzonenausbildungen unterschieden: ein verformungsinduzierter und ein thermisch induzierter Typ. Durch Abschätzen der Temperaturgradienten und der Blitztemperaturen konnte gezeigt werden, daß beim Schleifen mit Korundschleifscheiben lokale Anschmelzungen an Kontaktpunkten auftreten können. Ist die Wärmeleitfähigkeit des Schleifmittels wesentlich höher als die des Werkstückmaterials, so sind geringere Blitztemperaturen zu erwarten. Vor diesem Hintergrund bieten CBN-Schleifscheiben beim Schleifen des Fußprofils an Turbinenschaufeln eine Alternative zum Schleifen mit Korund.
  • Publication
    Öl-Luftschmierung von Wälzlagern
    ( 1992)
    Spur, G.
    ;
    Göke, U.
    The successful application of the oil/air lubrication presupposes the favourable setting of the parameters. This report deals with results based on a statistical design of experiments. A test stand with a spindel/bearing system has been built to measure the temperature rise at the inner race way of an angular contact ball bearing, it's friction torque and the change of preload. The values to be variied were the viscosity of the oil, the position of the nozzle, the oil and the air volume.