Neueste Publikationen

[ 1 ] Klenk, F.; Gallei, M.; Wurster, M.; Wagner, M.; Peukert, S. & Lanza, G. (2022), „Potential assessment of an increased exchange of core information for remanufacturing in automotive reverse supply chains“. The 29th CIRP Conference on Life Cycle Engineering, Hrsg. Dewulf, W. & Duflou, J., Elsevier, S. 446-451. 10.1016/j.procir.2022.02.074
Abstract
An increasing awareness of sustainability and scarcity of resources requires to enhance a product’s lifetime. Within the context of a circular economy, remanufacturing therefore can be applied. Used products (so-called ‘cores’) are returned to at least their original performance. An efficient planning and management of reverse supply chains (RSC) is a prerequisite for successful remanufacturing. Besides the required material flow from the customer via service centers, collection stations, and core brokers to the remanufacturing plants, the reverse flow of core information is essential. The multi-tier exchange of core information potentially facilitates reducing existent uncertainties in RSC, i.e. regarding timing, quantity, and quality of returned products. Yet, current approaches neither consider the multi-tier information flow nor the differentiation of core information for different downstream tasks in detail. Specifically, information flow in the automotive RSC remains to be researched in detail. Therefore, the potential of an increased exchange of core information for remanufacturing in RSC is explored in this paper. A literature review and expert interviews with the stakeholders in the automotive RSC are conducted to assess the status quo of information exchange. Based on this, relevant core-specific information, and their impact on increasing the efficiency of different downstream planning processes are identified. To quantify the potential of an increased information exchange, both a model for the categorical use of information and a receptor model are developed. It can be concluded that an increase in the exchange of information in remanufacturing goes along with a multitude of facilitations, e.g. regarding logistics optimization, material requirement planning and stochastic routing of cores. Moreover, due to the prioritization of core information, a sequence model for core information retrieval can be derived.

[ 2 ] Klenk, F.; Kerndl, F.; Heidinger, F.; Benfer, M.; Peukert, S. & Lanza, G. (2022), „Product networks and network configuration in global production networks“, Production Engineering, 10.1007/s11740-022-01149-4
Abstract
Driven by an increasing demand for individualized products and shorter product life-cycles, companies continuously extend their product portfolio. Simultaneously, companies expand into new markets to reach customers and to exploit varying location factors to reduce costs. Global production networks (GPNs) have to be adapted constantly to react to new circumstances and changes in the demand of products. To remain competitive, product allocation and production network configuration are essential. At the same time, companies face an increasing complexity while handling these tasks. This poses a challenge particularly for small and medium sized companies, which have limited planning capacities and management resources. Current literature describes optimization-based approaches for the integrated product allocation and network configuration of production networks. Yet, multi-objective models lack transparency of results and user friendliness. Therefore, this paper presents a multi-objective optimization model that incorporates flexibility and reconfiguration aspects to determine an optimal product allocation and network configuration of a GPN over a given planning horizon. The preemptive goal programming approach is used to identify Pareto-optimal solutions and to increase user friendliness. The subsequent verification, validation and post-optimality analysis combined in a structured process enables a wide range of companies to apply the approach. The model is successfully applied in the GPN of a special machine manufacturer, which produces high precision metrology machines. Due to its transparent approach for complex planning problems, the developed method provides a solid base for well-founded, objective decisions. Hence, the risk of costly errors in the planning phase is reduced.

[ 3 ] Husseini, K.; Schmidgruber, N.; Weinmann, H.; Maibaum, K.; Ruhland, J. & Fleischer, J. (2022), „Development of a Digital Twin for Improved Ramp-Up Processes in the Context of Li-Ion-Battery-Cell-Stack-Formation“. Procedia CIRP Volume 106, Elsevier, S. 21-26. 10.1016/j.procir.2022.02.150
Abstract
The ramp-up of machines for stack formation processes in the context of battery cell production is difficult due to a lack of knowledge about cause-effect relationships. This concerns the initial setup of the machine as well as the change of process input variables. For example, there are strong material dependencies in the area of cell stack formation of battery cells. Individual adjustments of the machine parameters to the different materials are therefore necessary. Digital twins represent the production process and the machine operations in a virtual environment. Cause-effect relationships can thus be quantified and evaluated. Optimization approaches for ramp-up-processes can be tested with low risk in virtual space before they are implemented in reality. This paper describes the development process of a digital twin representing a machine for flexible cell stack formation of pouch cells. As basis for the digital twin, a kinematic process model of the machine is developed from the underlying CAD files. Sensors and actuators are virtually integrated in the design environment of the machine. Connecting the model to a virtual controller, allows virtual testing and evaluating of the developed PLC code within the digital twin. Furthermore, the development of a simulation model for the prediction of the electrode web tension, as a quality-critical parameter, is presented. This purpose requires relevant aspects of the machine, for example the unwinder drive behaviour, to be recognized and integrated. In order to enable near-real-time runability, this simulation model is converted into a reduced-order-model. This substitution can be validated by tracing and comparing the web tension during commissioning scenarios on the real machine. Therefore it is possible to virtually represent control-side kinematic processes while also making statements regarding the web tension of the electrode material. The resulting functional digital twin of the flexible stack formation machine will be used to optimize the process parameters as well as the current machine design.

[ 4 ] Schmidgruber, N. & Fleischer, J. (2022), „Limitationen in der formatflexiblen Herstellung von Pouchfolie-Halbschalen“.
Abstract
Durch ihre hohe gravimetrische Energiedichte, sowie die niedrigen Stückkosten ihrer namensgebenden Verpackung aus Pouchfolie sind Pouchzellen eine vielversprechende Zell-Bauweise. Als weiterer Vorteil der Pouchzelle gilt ihre vergleichsweise gute Flexibilität hinsichtlich unterschiedlicher Formate. Eine flexible Zellproduktion ermöglicht Herstellern eine Differenzierungsstrategie gegenüber dem stark formatgebundenen Markt. Um die Vorteile der Pouchzelle in der Formatflexibilität ausspielen zu können, muss neben Zellstapelbildung und Zellassemblierung auch die Herstellung der Pouchfolie-Halbschalen flexibilisiert werden. Es lassen sich drei relevante Aspekte für die Flexibilisierung der Halbschalenproduktion ausmachen: Das verwendete Folienmaterial, die Ziehtiefe und die Geometrie des Werkzeugs. Im Rahmen dieses Posters werden diese Aspekte diskutiert und ihre jeweiligen Limitationen aufgezeigt.

[ 5 ] Schmidgruber, N.; Hofmann, J. & Fleischer, J. (2021), „Hocheffiziente Fertigungsmodule für Li-Ion Zellen mit hochpräzisen Presseneinheiten“.
Abstract
Die Prozesskette der Pouchzelle enthält eine Vielzahl vertikaler Bewegungen die hochpräzise Kraft-Weg Regelungen benötigen. Während Produktionsanlagen für Batteriezellen in Deutschland noch immer Sondermaschinen darstellen, besitzen viele Anlagenbauer umfangreiche Kompetenzen in der Produktionstechnik. Gerade Pressenhersteller besitzen umfangreiche Kompetenzen in der Kraft-Weg Regelung, sind in der Batterie-Produktion jedoch noch unterrepräsentiert. Möglichkeiten diese Kompetenzen zu übertragen werden in diesem Poster untersucht.

Weitere Publikationen finden Sie hier: