Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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Werkzeuge effizient reparieren

2023-08-01 , Mönchinger, Stephan , Müller, Vinzenz

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Investigation of the LME Susceptibility of Dual Phase Steel with Different Zinc Coatings

2023-05-05 , El-Sari, Bassel , Biegler, Max , Rethmeier, Michael

The application of anti-corrosion coated, high-strength steels in the automotive industry has increased in recent years. In combination with various zinc-based surface coatings, liquid metal embrittlement cracking can be observed in some of these materials. A high-quality, crack-free spotwelded joint is essential to realize the lightweight potential of the materials. In this work, the LME susceptibility of different coatings, which will be determined by the crack length and the occurrence rate, will be investigated using a welding under external load setup. The uncoated specimens did not show any LME. EG, GI and GA showed significantly less LME than ZM coatings. The latter coatings showed much larger crack lengths than the EG, GI and GA coatings. Furthermore, two mechanisms regarding the LME occurrence rate were observed: the occurrence of LME in zinc-magnesium coatings was theorized to be driven by the material properties of the coatings, whereas the occurrence of LME at EG, GI and GA samples was forced mainly by the application of the external tensile load. In the experimental setup of this work, the materials were exposed to unusually high mechanical loads (up to 80% of their yield strength) to evoke LME cracks.

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Empowering End-of-Life Vehicle Decision Making with Cross-Company Data Exchange and Data Sovereignty via Catena-X

2023 , Mügge, Janine , Große Erdmann, Julian , Riedelsheimer, Theresa , Manoury, Marvin Michael , Smolka, Sophie Odette , Wichmann, Sabine , Lindow, Kai

The mobility sector is the world’s second-largest producer of energy-related CO2 emissions, and it is facing a global resource shortage. The demand for circular products, the use of secondary materials in future vehicles, and the need for sustainable business models in the mobility sector is increasing. However, a transparent and end-to-end data exchange throughout the entire value network is missing, which is hindering an efficient circular economy. Relevant information on the vehicle, its components, and materials at the end of the product life cycle are often missing. In this context, this paper presents a decision support system based on Digital Twin data for a circular economy solution as a software application. It was developed within the German research project Catena-X following an integrated approach of user-centered design, the V-model, and within the Scaled Agile Framework. By combining these methodological approaches, customer-oriented solutions were developed and continuously improved at each stage of development to shorten the time-to-market. Catena-X is based on Gaia-X principles. In Gaia-X, necessary core services are developed, and contraction negotiation for data exchange and usage policies is enabled and implemented. The decision support system provides important information about the exact composition and condition of the vehicle, its components, and its materials. Thus, it helps to improve efficiency, sustainability, and the implementation of the circular economy. The decision support system was tested and validated with a use case that provided Digital Twin data on the end-of-life vehicle.

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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.

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Sustainable product lifecycle management with Digital Twins: A systematic literature review

2023-07 , Seegrün, Anne , Kruschke, Thomas , Mügge, Janine , Hardinghaus, Louis , Knauf, Tobias , Riedelsheimer, Theresa , Lindow, Kai

A Digital Twin (DT) is a virtual replica of a product or product-service system, which can be used to provide transparency of a product's sustainability and to positively influence the ecological impact throughout its lifecycle by means of intelligent data analytics. This paper identifies current sustainability-focused application scenarios of DTs in the manufacturing industry and outlines the results of a systematic literature review (SLR). The identification of the state-of-the-art and the assessment of current DT concepts with regard to the addressed product lifecycle phases, technological maturity and sustainability scope point towards key directions to guide future research.

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Adaptive Reparatur-Prozesskette

2023-02-11 , Müller, Vinzenz , Mönchinger, Stephan , Colombo, Giovanna Fiocco , Biegler, Max , Rethmeier, Michael

Das additive Fertigungsverfahren Laser-Powder Directed Energy Depositon (LP-DED), kombiniert mit automatisierten Reverse-Engineering-Ansätzen, bietet die Möglichkeit, Bauteile effizient zu reparieren. Durch intelligente Algorithmen können im sogenannten Scangineering 3D-Scandaten von Bauteilen vorverarbeitet, ausgerichtet und parametrisiert werden. Die erkannten geometrischen Defekte werden zur Errechnung der Werkzeugwege für den additiven Aufbau verwendet und mittels des LP-DED-Prozesses aufgeschweißt und repariert. Dabei kommen vor allem die Vorteile der flexiblen Prozessführung, ein hoher Automatisierungsgrad und gute Reproduzierbarkeit zum Tragen.

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Integrated Disturbance Observer-Based Robust Force Control

2023 , Kangwagye, Samuel , Haninger, Kevin , Oboe, Roberto , Oh, Sehoon

For robotic tasks that involve combined transmitting and contact force control, achieving the high-performance motion control while ensuring stable environment contact is difficult. Among the factors that affect the quality of this force control, in this article, we may account vibrations due to misalignment in the mechanical components, actuator inaccuracies, nonlinear effects of friction, and backlash. All the above mentioned factors can be collectively considered as force disturbances. Toward high-performance motion control and contact stability, a novel integrated disturbance observer (DOB) (IDOB) is proposed. The IDOB uses force sensor measurements with position measurements and a plant model to isolate and robustly suppress the effects of force disturbances within the plant without compromising contact stability. This is applied here to a force control system to demonstrate the enhanced force control performance in free space and in contact. The passivity, robust stability, and disturbance rejection of the proposed IDOB are compared with those of existing force controllers, with and without force-based DOBs. Finally, actual experiments are conducted in free space and contact under various interaction conditions, showing that the IDOB improves transmitting force control and disturbance suppression performances. Moreover, peak collision force is reduced while maintaining contact stability with stiff environments.

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Brennstoffzelle - wie sauber muss es sein?

2023-06-29 , Tammer, Christoph , Schießl, Timo , Burgdorf, Philipp

Die technische Sauberkeit ist bei der Brennstoffzelle eine wichtige Einflussgröße für die realisierte Produktqualität in Bezug auf Lebensdauer und Performanz. Wie an welcher Stelle der Prozesskette im Hinblick auf welche Grenzwerte gereinigt und geprüft werden sollte, wird aktuell im Rahmen eines Forschungsprojektes betrachtet.

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Green incremental learning - Energy efficient ramp-up for AI-enhanced part recognition in reverse logistics

2023 , Schlüter, Marian , Schimanek, Robert , Koch, Paul , Briese, Clemens , Chavan, Vivek Prabhakar , Bilge, Pinar , Dietrich, Franz , Krüger, Jörg

Artificial Intelligence (AI) has made significant progress in supporting circular economy and reverse logistics by learning from diverse data to predict, e.g., routes or to assist workers in sorting. However, it remains an open question how AI can be integrated and trained into such operational processes, where little to no data has been collected previously. Traditionally, AI models would only be rated by their accuracy. This paper aims to introduce the concept of green incremental learning, i.e. rating AI models not only for their accuracy but to evaluate energy efficiency as well. A ramp-up of a data-driven AI system for part recognition is explored under consideration of energy efficiency. Therefore, we combine online and incremental learning, working with growing data sets to simulate a ramp-up phase. We present experiments of incremental learning on business and image data, partially supported by regular joint training steps. We start local CPU-based machine learning and prediction on business data from the first sample. Finally, we compare incremental learning to traditional batch learning and show energy-saving potential of up to 62 % without a significant drop in accuracy.

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Implementing digital twins in existing infrastructures

2023 , Lünnemann, Pascal , Lindow, Kai , Goßlau, Leo

Digital twins can offer various added values for companies. As part of a three-year research project, we are investigating the methodological approach, for building digital twins in existing infrastructures. In particular, the functional requirements of future users will be addressed, as this is less focused in existing approaches. Within the framework of this publication, we discuss the applied methodology as well as the created models and concepts. Initial insights were gained in the simultaneous development of digital twins in parallel projects with use cases for electric motors, production process monitoring and maintenance of gas turbine components. In detail, it becomes clear that software development methods (e.g. use cases, user stories, scenario development) are a good way to describe the expected added value functions. It is essential to involve the future users in the development as early as possible. Transferring the necessary functions identified in this way into a functional architecture shows that this architecture is mostly independent of the use case. Likewise, the IT systems used here hardly vary at all. Overall, it shows that a methodical approach can be followed in the development and the implementation can have a high degree of similarity, even in very different use cases, while the exact design, depending on these use cases, is very diverse.

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