Now showing 1 - 10 of 292
  • Publication
    Result quality evaluation of Directed Energy Deposition Additive Manufacturing simulations with progressive simplification of transient heat-source motion
    ( 2022-09-05) ;
    Elsner, Beatrix A.M.
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    Neubauer, Ingo
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    Directed Energy Deposition (DED) additive manufacturing has recently been adopted in the industry for the build-up of structural components with weld lengths up to kilometers. As with all welding processes, DED suffers from thermal distortion, causing loss of dimensional accuracy and risk of cracking. Currently, process optimization with objective to minimize distortion requires expensive experimental trial-and-error. With numerical simulation of the DED process, this distortion compensation can be performed virtually, significantly reducing experimental trials. Although such approaches are generally available, their widespread adoption is currently being hampered by long computational times for large builds. This work presents a novel approach to reduce the calculation time by a simplification of the transient heat-source motion. This approach is assessed in terms of result accuracy for an industrial-scale component by progressively reducing the resolution of the heat-source motion. Calculation times as well as distortions in comparison to experimental trials are investigated.
  • Publication
    Investigation of liquid metal embrittlement avoidance strategies for dual phase steels via electro-thermomechanical finite element simulation
    ( 2022-06) ;
    Böhne, Christoph
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    Meschut, Gerson
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    Modern advanced high-strength steel (AHSS) sheets used in automotive body construction are mostly zinc coated for corrosion resistance. The presence of zinc can cause cracking in steels due to liquid metal embrittlement (LME) during resistance spot welding (RSW). In combination with factors such as tensile strains, liquid zinc can lead to the formation of brittle, intergranular cracks in the weld and heat affected zone. While practical investigations to mitigate LME occurrence exist, the reason why a certain parameter might cause or prevent LME is often unknown. Numerical resistance spot welding simulation can visualize the underlying stresses, strains and temperatures during the welding process and investigate experimentally unmeasurable phenomena. In this work, a 3-dimensional electro-thermomechanical finite element approach is used to assess and investigate the critical parameters leading to LME occurrence. Experimentally observed crack sizes are correlated with the corresponding local strain rates and temperature exposure durations in the simulation. With this data, a map of LME occurrence over driving influence factors is drafted and discussed for effectiveness.
  • Publication
    Integrated weld preparation designs for the joining of L-PBF and conventional components via TIG welding
    ( 2022-04-18)
    Geisen, Ole
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    Graf, Benjamin
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    Laser powder bed fusion (L-PBF) of entire assemblies is not typically practical for technical and economic reasons. The build size limitations and high production costs of L-PBF make it competitive for smaller, highly complex components, while the less complex elements of an assembly are manufactured conventionally. This leads to scenarios that use L-PBF only where it's beneficial, and it require an integration and joining to form the final product. For example, L-PBF combustion swirlers are welded onto cast parts to produce combustion systems for stationary gas turbines. Today, the welding process requires complex welding fixtures and tack welds to ensure the correct alignment and positioning of the parts for repeatable weld results. In this paper, L-PBF and milled weld preparations are presented as a way to simplify the Tungsten inert gas (TIG) welding of rotationally symmetrical geometries using integrated features for alignment and fixation. Pipe specimens with the proposed designs are manufactured in Inconel 625 using L-PBF and milling. The pipe assembly is tested and TIG welding is performed for validation. 3D scans of the pipes before and after welding are evaluated, and the weld quality is examined via metallography and computed tomography (CT) scans. All welds produced in this study passed the highest evaluation group B according to DIN 5817. Thanks to good component alignment, safe handling, and a stable welding process, the developed designs eliminate the need for part-specific fixtures, simplify the process chain, and increase the process reliability. The results are applicable to a wide range of components with similar requirements.
  • Publication
    Quality Prediction in Directed Energy Deposition Using Artificial Neural Networks Based on Process Signals
    ( 2022-04-14)
    Marko, Angelina
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    Bähring, Stefan
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    Raute, Maximilian Julius
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    The Directed Energy Deposition process is used in a wide range of applications including the repair, coating or modification of existing structures and the additive manufacturing of individual parts. As the process is frequently applied in the aerospace industry, the requirements for quality assurance are extremely high. Therefore, more and more sensor systems are being implemented for process monitoring. To evaluate the generated data, suitable methods must be developed. A solution, in this context, was the application of artificial neural networks (ANNs). This article demonstrates how measurement data can be used as input data for ANNs. The measurement data were generated using a pyrometer, an emission spectrometer, a camera (Charge-Coupled Device) and a laser scanner. First, a concept for the extraction of relevant features from dynamic measurement data series was presented. The developed method was then applied to generate a data set for the quality prediction of various geometries, including weld beads, coatings and cubes. The results were compared to ANNs trained with process parameters such as laser power, scan speed and powder mass flow. It was shown that the use of measurement data provides additional value. Neural networks trained with measurement data achieve significantly higher prediction accuracy, especially for more complex geometries.
  • Publication
    Learning Demonstrator for Anomaly Detection in Distributed Energy Generation
    ( 2022-04-07)
    Pelchen, Timo
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    Thiele, Gregor
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    Radke, Marcel
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    Schade, David
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    Machine learning based anomaly detection methods on process data can be used to secure critical infrastructure. The design and installation of these methods require detailed understanding of both the facilities and the machine learning methods. Therefore, they are mostly incomprehensible for non-experts and thus acting as a barrier hindering the fast spread of such technologies. This article presents the systematic development of a demonstrator which enables presentations of anomaly detection on the example of a simulated wind farm. The specially designed user-interface allows a comprehensive experience. This article documents the use of the demonstrator for experts experienced in energy systems which are interested in the application of machine learning algorithms.
  • Publication
    Skalierbare Herstellung von ATMPs
    Die Entwicklung von Arzneimitteln für neuartige Therapien (ATMPs; Advanced Therapy Medicinal Products) schreitet schnell voran. Erste Produkte haben bereits die Marktzulassung erhalten und sind kommerziell erhältlich. Ihre Produktion ist jedoch von komplexen manuellen Abläufen, hochspezialisierten Geräten und den damit verbundenen hohen Produktionskosten geprägt. Aufgrund der Neuartigkeit und der hohen Komplexität bei der Produktion kann das volle klinische Potential von ATMPs in Zukunft unter den bestehenden Produktionsbedingungen nicht ausgeschöpft werden. Darüber hinaus nehmen die am Markt zugelassenen Produkte und die klinischen Anwendungsgebiete von ATMPs stetig zu, was langfristig nicht nur zu einem Engpass in der Produktion, sondern auch zu einer hohen finanziellen Belastung des Gesundheitssystems führen wird. Um die Herstellkosten von ATMPs zu senken und sie vielen Patientinnen und Patienten zur Verfügung stellen zu können, sind neue Konzepte entlang der gesamten Wertschöpfungskette erforderlich. Dafür muss die Produktion insbesondere stärker automatisiert und digitalisiert werden. Unterschiedliche Konzepte sind hier vielversprechend für eine vollautomatisierte Produktion, im Sinne einer vollintegrierten Automatisierung oder eines modularen Aufbaus der Produktionsumgebung. Die Implementierung dieser Konzepte setzt neue Entwicklungen voraus, von der Entnahme der Zellen bei der Spenderin oder beim Spender über die Produktionstechnologien an sich bis hin zur finalen Formulierung und Abfüllung des Produkts. Neben Änderungen im Bereich der Hardware werden auch neue Softwarelösungen notwendig, beispielsweise zur Planung und Auswahl geeigneter Produktionsszenarien. Auch für die eigentliche Produktion von ATMPs und die damit verbundenen Daten müssen zukünftig neue Technologien, wie bspw. integrierte Prozesskontrollen, die Prozessbegleitung mittels Digitalem Zwilling oder die Analyse sowie Prozesssteuerung mittels Künstlicher Intelligenz (KI) berücksichtigt werden, um das volle Automatisierungspotential ausschöpfen zu können.
  • Publication
    16. Berliner Runde. Neue Konzepte für Werkzeugmaschinen. Begleitband
    (Fraunhofer IPK, 2022)
    Produktionstechnik als Vorreiter für Lösungen einer sich wandelnden Industriegesellschaft: Klimaschutz und Ressourcenknappheit, Digitalisierung und Daten sicherheit, Urbanisierung und Mobilität sind globale Themen, die zu einem Wandel unserer Industriegesellschaft führen. In ihrer 16. Auflage rückt die Berliner Runde, das führende Forum für Werkzeugmaschinenhersteller, Zulieferer und Anwender, Lösun gen aus der Produktionstechnik in den Fokus, mit denen Unter nehmen Herausforderungen und Potenziale dieses disruptiven Wandels gleichermaßen bewältigen und ausschöpfen können. Die Themen umfassen unter anderem nachhaltige Fertigungs- und Maschinentechnologien, ganzheitliche Optimierungskon zepte mithilfe Künstlicher Intelligenz, kontextsensitive Assistenz systeme sowie Lösungen aus den Bereichen Blockchain und Health Science. Die vorgestellten Lösungsansätze bieten einen neuen Blickwinkel auf die Produktion von morgen und ermögli chen es Unternehmen, in dem vorherrschenden Spannungsfeld auch zukünftig wirtschaftlich effizient zu agieren. Hochrangige Referentinnen und Referenten aus dem Werkzeug maschinenbau, der gesamten Lieferkette sowie der Anwendung stellen aktuelle und zukünftige Entwicklungen der Werkzeug maschinenbranche sowie der Produktionstechnik vor. Diskutieren Sie mit uns, welche System- und Komponentenlösungen neue Impulse für einen zukunftsorientierten Wandel unserer Industrie gesellschaft setzen können und welche innovativen Lösungen für die Produktionstechnik daraus resultieren.
  • Publication
    Modellieren von Widerstandspunktschweissungen in FE
    In der Veröffentlichung wird anwendungsbezogen die Simulation von Widerstandpunktschweißungen in FEA-Programmen erklärt. Hierbei wird insbesondere der Nutzen für den praxisorientieren Schweißingenieur/Produktionsplaner erläutert und wie dieser die Schweißstruktursimulation nutzen kann, um Schweißverzug vorherzusagen und diesen zu minimieren.
  • Publication
    Impact of COVID-19 on production
    This study examined the direct impacts of COVID-19 on industrial production. The focus is on the question: How can digitalization help mitigate the impact? The aim of the survey is to first review the situation and then look ahead to find out how manufacturing companies rate the future and would like to shape it. The current results of the study form the basis for recommendations for action with regard to technologies and supporting services for manufacturing companies.
  • Publication
    Requirements-driven Identification and Validation of Reusable System and Development Elements
    (Fraunhofer Verlag, 2021)
    Sünnetcioglu, Atakan
    The well-known benefits of reuse in product development are reduced necessary effort, shorter development cycles and increased product quality due to the more mature solutions that are integrated into new products. Although it sounds paradox, reusing existing solutions in new development projects is one of the possibilities to increase the innovation power of a company. By applying reuse in a systematic way where applicable, product development teams can create additional resources for more innovative aspects of new products. This book reveals a requirements-driven approach for the identification of reuse in development projects. In this approach, product developers compare requirements of ongoing and completed projects to identify related requirements, which are suitable for reuse since they can be fulfilled with same solutions. However, comparison of requirements specifications is an elaborate and time consuming task for product developers.