Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Fully coupled wet cylindrical turning simulation using the Finite-Pointset-Method
    ( 2021)
    Uhlmann, Eckart
    ;
    Barth, Enrico
    ;
    Quellhorst, Alexander
    ;
    Seifarth, Tobias
    ;
    Kuhnert, Jörg
    ;
    Nabbout, Kaissar
    ;
    Sommerfeld, Martin
    In 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.
  • Publication
    Data for a simulation of metal cutting with cutting fluid using the Finite-Pointset-Method
    ( 2021)
    Uhlmann, Eckart
    ;
    Barth, Enrico
    ;
    Seifarth, Tobias
    ;
    Höchel, Maximilian
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    Kuhnert, Jörg
    ;
    Eisenträger, Almut
    The 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.
  • Publication
    Optimization with the evolution strategy by example of electrical-discharge drilling
    ( 2020)
    Streckenbach, Jan
    ;
    Koref, Ivan Santibáñez
    ;
    Rechenberg, Ingo
    ;
    Uhlmann, Eckart
    A key challenge in electrical discharge machining (EDM) is to find a suitable combination out of numerous process parameters. Any changes concerning the electrode materials or geometries require newly optimized technologies. These technologies are to be developed from a considerable number of experiments which must be carried out by an experienced operator. This paper presents a new method of finding the optimal set of parameters. Here, the performance of the evolution strategy (ES), a stochastic, metaheuristic optimization method, is investigated. It offers the great advantage of finding solutions, even with little knowledge of system behaviour. The method involved a randomized and a derandomized ES, based on a non-elitist (m,l)-ES with one parent and four children. The two ES were initialized from an unfavourable starting point (A) and from a favourable starting point (B) to investigate their effectiveness. It could be demonstrated that starting from the unfavourable starting point A the erosion duration tero could be reduced by a maximum of 77% with a slightly smaller linear wear of the tool electrode DlE after 40 trials.
  • Publication
    Investigating three-dimensional sketching for early conceptual design - results from expert discussions and user studies
    ( 2009)
    Israel, J.H.
    ;
    Wiese, E.
    ;
    Mateescu, M.
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    Zöllner, C.
    ;
    Stark, R.
    As immersive 3D user interfaces reach broader acceptance, their use as sketching media is attracting both commercial and academic interests. So far, little is known about user requirements and cognitive aspects of immersive 3D sketching. Also the latter's integration into the workflow of virtual product development is far from being solved. We present results from two focus group expert discussions, a comparative user study on immersive 3D sketching conducted among professional furniture designers and a qualitative content analysis of user statements. The results of the focus group discussions show a strong interest in using the three-dimensional (3D) space as a medium for conceptual design. Users expect it to provide new means for the sketching process, namely spatiality, one-to-one proportions, associations, and formability. Eight groups of functions required for 3D sketching were outlined during the discussions. The comparative study was intended to find and investigate advantages of immersive three-dimensional space and its additional degrees-of-freedom for creative/reflective externalization processes. We compared a 3D and a 2D baseline condition in the same technical environment, a VR-Cave system. In both conditions, no haptic feedback was provided and the 2D condition was not intended to simulate traditional 2D sketching (on paper). The results from our user study show that both the sketching process and the resulting sketches differ in the 2D and 3D condition, namely in terms of the perceived fluency of sketch creation, in terms of the perceived appropriateness for the task, and in terms of the perceived stimulation by the medium, the movement speed, the sketch sizes, the degree of detail, the functional aspects, and the usage time. In order to validate the results of the focus group discussions, we produced a questionnaire to check for the subjectively perceived advantages and disadvantages in both the 2D and 3D conditions. A qualitative content analysis of the user statements revealed that the biggest advantage of 3D sketching lies in the sketching process itself. In particular, the participants emphasized the system's ability to foster inspiration and to improve the recognition of spatiality and spatial thinking. We argue that both 2D and 3D sketching are relevant for early conceptual design. As we progress towards 3D sketching, new tangible interactive tools are needed, which account for the user's perceptual and cognitive abilities.
  • Publication
    InViS - Integrierter Virtueller Schiffbau
    ( 2004)
    Lukas, U. von
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    Schulte, G.
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    Hayka, H.
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    Scheller, M.
    ;
    Wolf, A.
    Der Beitrag stellt wesentliche Ergebnisse des BMBF-Projekts InViS - Integrierter Virtueller Schiffbau vor. Hierzu zählen das als XML-Schema codierte Datenmodell, die offene Integrationsplattform sowie verschiedene darauf aufbauende Komponenten für Telekooperation, VR-Präsentation, Simulation und Anbindung von CAD-Systemen. Die Projektergebnisse werden im Kontext des Virtuellen Maschinenraums in zwei Anwendungsszenarien evaluiert und verdeutlichen das Potential des integrativen Ansatzes zur Unterstützung durchgängiger Prozessketten.