Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Nachhaltige Reinigung und Präparation
    ( 2024)
    Uhlmann, Eckart
    ;
    Polte, Julian
    ;
    Burgdorf, Philipp
    ;
    Reder, Waldemar
    In der Fertigungstechnik lautet aktuell die Devise, innovative Wege für mehr Nachhaltigkeit zu entdecken. Für industrielle Reinigungsprozesse ist das CO2-Strahlen auf dem Vormarsch - im Beitrag wird beschrieben, warum.
  • Publication
    Echtzeit-Energieüberwachung in der Funkenerosion
    ( 2023)
    Uhlmann, Eckart
    ;
    Polte, Mitchel
    ;
    Yabroudi, Sami
    ;
    Thißen, Kai
    ;
    Penske, Wilhelm
    Ein großes Optimierungspotenzial der Funkenerosion liegt in den Energien der einzelnen Entladungen verborgen. Eine vektorielle Bestimmung der Entladedauern und die darauf basierende Energieberechnung sowie Klassifizierung erlauben es, die Entladeenergien, Entladungsarten und -dauern in Echtzeit zu überwachen und zu analysieren. Möglich wird dies durch ein Multiprocessing-Erzeuger-Verbraucher-Schema, welches überdies eine Visualisierung und Auswertung der Messdaten erlaubt.
  • Publication
    Edge Computing Software für den Zerspanungsprozess
    ( 2023)
    Uhlmann, Eckart
    ;
    Hocke, Toni
    ;
    Heper, Martin
    ;
    Polte, Mitchel
    In aktuellen Forschungsprojekten entwickeln Forscher des Instituts für Werkzeugmaschinen und Fabrikbetrieb (IWF) Open-Source-Software für Edge Devices. Für die Auslegung der Fertigungsprozesse wird neben den ingenieurwissenschaftlichen Themen auch exemplarisch die Auslegung einer entwickelten Auswerteelektronik inklusive der Softwarebereitstellung adressiert. Der interdisziplinäre Ansatz, einschließlich der Softwarebereitstellung, wird exemplarisch an einem DFG-Projekt zur Prozessüberwachung bei der Ultrapräzisionsdrehbearbeitung diskutiert.
  • Publication
    Cooling Capacity of Oil-in-Water Emulsion under wet Machining Conditions
    ( 2023)
    Nabbout, Kaissar
    ;
    Sommerfeld, Martin
    ;
    Barth, Enrico
    ;
    Uhlmann, Eckart
    ;
    Bock-Marbach, Benjamin
    ;
    Kuhnert, Jörg
    Many 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.
  • Publication
    Enabling of Automatically Generation of Cutting Paths for Three-Dimensional Pre-Contouring with Waterjet Trimming
    ( 2023)
    Reder, Waldemar
    ;
    Uhlmann, Eckart
    Abrasive Water Injector Jet Cutting (AWIJC) is a flexible machining process for manufacturing high-performance materials, such as titan-and nickel-base-alloys. Due to the low ductility and thermal conductivity of these materials, conventional machining is struggling with high tool costs and wear. The tool wear in AWIJC is independent of the machined material, and the process has the potential to provide a cost-efficient solution in machining high-performance materials. Trimming, a near-net-shape pre-contouring with multi-stage AWIJC, requires a detailed knowledge of cutting paths for all steps in advance. In order to enable a geometrical flexible manufacturing process, an automatically cutting path generation is necessary. This article presents an application developed with NX Open using Visual Basic. The application TrimCAD is able to provide all necessary geometries for trimming based on the geometries of initial and finished parts. Furthermore, it is possible to adjust the number of cuts and the degree of pre-contouring. All geometries are automatically exported as a standardized three-dimensional STEP-file. The STEP-geometries can be processed to the CAM-processor of the waterjet machine. TrimCAD is an innovative possibility to machine three-dimensional parts made of high-performance materials.
  • Publication
    Smarte Überwachung elektrischer Großantriebe
    ( 2023)
    Geisert, Claudio
    ;
    Polte, Julian
    ;
    Uhlmann, Eckart
    ;
    Rauch, Hartmut
    ;
    Brach, Karsten
    Die Nutzung von Digitalisierungstechnologien im Kontext von Industrie 4.0 bietet insbesondere für den gesamten Bereich der Wartung und Instandhaltung von elektrischen Großantrieben großes Potenzial zur Schaffung innovativer Serviceangebote. Durch erweiterte Sensorik im elektrischen Antrieb und Intelligenz in der Verarbeitung und Analyse von Daten im Betrieb von Anlagen, kann eine vorausschauende Instandhaltungsstrategie eingeführt werden, die eine höhere Verfügbarkeit der Anlagen ermöglicht und gleichzeitig den Aufwand für Instandhaltungseinsätze reduziert. Um diese Potenziale im Servicegeschäft elektrischer Großantriebe zu erschließen, wird in diesem Beitrag ein hypothesengetriebener Ansatz zur Zustandsüberwachung beschrieben.
  • Publication
    High-Performance Electro-Discharge Drilling with a Novel Type of Oxidized Tool Electrode
    ( 2022)
    Uhlmann, Eckart
    ;
    Polte, Julian
    ;
    Streckenbach, Jan
    ;
    Dinh, Ngoc Chuong
    ;
    Yabroudi, Sami
    ;
    Polte, Mitchel
    ;
    Börnstein, Julian
    Electro-discharge drilling is a key technology for manufacturing sophisticated nozzles in a broad range of automotive and aerospace applications. The formation of debris in the working gap leads to arcs and short circuits on the lateral surface when state-of-the-art tool electrodes are used. As a result, limited drilling depth, increased linear tool wear, and the conicity of boreholes are still challenges. In this work, a new approach for the passivation of the lateral surface of copper tool electrodes by oxidation is shown. The comparison with state-of-the-art tool electrodes showed a reduction in the erosion duration by 48% for machining hardened steel. Promising improvements could be achieved by the thermal oxidation of the tool electrodes with the aim of increasing the electrical resistivity of the lateral surface of the tool electrode. However, due to the loss of strength, the high oxide layer thickness, and the partial delamination of the oxide layer, further comprehensive investigations on the influence of the oxidation temperature need to be conducted. Future adjustments with lower oxidation temperatures will be carried out.
  • Publication
    Comparing the performance of a nested to a continuous evolution strategy with covariance matrix adaption for optimization of drilling EDM
    ( 2022)
    Uhlmann, Eckart
    ;
    Streckenbach, Jan
    ;
    Polte, Mitchel
    ;
    Osmanovic, M.
    ;
    Schick, F.
    Electrical discharge machining (EDM) is a complex manufacturing process where the correlation of the individual process parameters is not fully known. When introducing new materials or complex, individual geometries in EDM, a satisfactory vector of parameters for the process must be found. This challenge is often encountered in the aerospace industry as well as in mold and tool making. One previously successful method to tackle this challenge is the stochastic optimization procedure Evolutionary Strategy (ES). Utilizing an appropriately chosen objective function, the search for a suitable vector of input parameters may be formulated as a mathematical minimization problem over the parameter space. The ES with a covariance matrix adaption (CMA) was utilized to sample from this parameter space in a stochastic manner. Examining the impact of the CMA within an ES is a promising way to gain better insight into the performance of ES. For this purpose, a vector of input parameters was optimized for a drilling EDM process with a comma and a nested comma ES with CMA. It was found that the comma ES led to a reduction in erosion duration tero of 38 % compared to the initially chosen parameters and the nested comma ES led to a reduction in erosion duration tero of 27 % compared to the same initial parameters. The additional information stored in the covariance matrix enables the ES to find a local optimum of the parameter vector faster and more consistently. This fact is verified by use of visualizations of the covariance matrix on a two-dimensional subspace. From these findings it can be concluded, that for the application of the ES to the optimization of EDM processes the CMA should be performed continuously over all generations as opposed to resetting this matrix after a number of generations.
  • Publication
    Novel Advances in Machine Tools, Tool Electrodes and Processes for High-Performance and High-Precision EDM
    ( 2022)
    Uhlmann, Eckart
    ;
    Polte, Mitchel
    ;
    Yabroudi, Sami
    High-performance electrical discharge machining (EDM) is a key technology for manufacturing high-precision components in a broad range of industrially relevant applications. Formation of debris in the working gap leads to arcing and short-circuits on the surface as well as related inaccuracies and process instabilities. Despite decades of research in the field of EDM excessive tool wear and limited process performance are still challenging. In order to overcome highly complex state-of-the-art challenges, dedicated processes, machine tools, peripheral systems, software, tool electrodes and technologies for the application of alternative dielectric fluids have been developed. Within this work novel advances in the development of a sophisticated dry EDM machine tool, including generator and process control technology based on open architecture, open source software, and commonly available machine tool components, are presented. Solutions for challenges regarding remaining debris and gas bubbles as well as related arc discharge and short-circuit pulses in sinking EDM are presented by new flushing methods, technologies and devices. A new system for inverted pressure flushing of a dielectric fluid in ED-drilling enables a highly efficient removal of debris and gas bubbles through the interior channels of the tool electrode. A new multi-luidic spindle system for EDM provides the ability to use performance- and material-related application of gaseous, near-dry and liquid dielectric fluids sequentially within a single machining process. Recent advances in tool electrode design, tool electrode material application, modification and production have led to essential process improvements. A helical tool electrode design significantly improved flushing conditions and related material removal rate in ED-drilling. Modification of ED-drilling tool electrode surfaces by thermal oxidation of copper reveals a promising approach to minimize ineffective discharges. Application of a specific mesophase-pitch carbon fiber with a diameter of df = 10 µm using a new process and handling technology enabled drilling holes with a diameter of dh = 25 µm. Next to the shown advances in EDM, efficient development of new process technologies could be enabled by using a specially adapted natural analogue algorithm software tool.
  • Publication
    Deliberate Surface Treatment of Zirconium Dioxide with Abrasive Brushing Tools
    ( 2022)
    Hoyer, Anton
    ;
    Uhlmann, Eckart
    Brushing with bonded abrasives is a flexible finishing process used to reduce the roughness of technical surfaces. Although industrially widespread, especially for the finishing of metallic surfaces, insufficient knowledge of the motion, the material removal, and the wear behavior of the abrasive filaments complicates predictions of the work result. In particular, the reliable finishing of ceramics with bonded diamond grains proves difficult due to increased material removal rates, quickly leading to undesirable changes in the workpiece geometry. Based on technological investigations with abrasive brushing tools, this article provides insights into the surface finishing of zirconium dioxide with a focus on finding compromises between reduction in the surface roughness and alteration of the workpiece shape.