Publications Search Results

Now showing 1 - 10 of 49
  • Publication
    Development of a Method to Increase Flexibility and Changeability of Supply Contracts in the Automotive Industry
    ( 2019)
    Niemann, Jens
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    Seisenberger, Stephan
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    The electric mobility market is characterized by demand volatility and a changing supply chain with new to the industry suppliers. In order to cope with demand volatility, the production capacities must be synchronized with external supply chain partners through changeability and flexibility measures. We define flexibility as the ability to quickly react to changing demand volumes within the current supply chain and production structure. Changeability needs further investments to adapt to the changing environment. This paper presents a method for the design of flexible and changeable supply chains, predicated on an examination of two companies' production systems and two different supply contract designs. We consider a quantity flexibility contract and a new developed contracting matrix. The method is being validated by a prototypical application in the production of electrified automotive powertrains. The results show an increase in supply chain flexibility for the quantity flexibility contract and we are able to introduce a changeable supply chain with the use of the contracting matrix.
  • Publication
    Load and energy management for factories through multi-stage production planning and optimization
    The production phase has a major influence on the embodied energy of many products and, thus, their overall environmental performance. As a result, manufacturing enterprises are prompted to raise their energy efficiency and flexibility to improve their products' sustainability. The simultaneous integration of renewable energy sources and decentral storages is a feasible option in this but also require consistent solutions for appropriately planning and controlling the operation of the entire factory system. This paper proposes an iterative multi-stage heuristic optimization for intelligent load and energy management. A load profile of the production plan, based on the minimized overall makespan, is checked against the available energy supply to identify demands and opportunities to shift single jobs based on calculated buffer times. Whenever infeasibility is determined, the process returns to the previous production planning stage for further alterations. This cycle is initiated regularly (e.g. weekly) or following certain events (e.g. long-lasting machine failure) and terminates once all restrictions are observed or if a termination threshold (e.g. calculation time) is reached. The experimental setup used for developing and validating this approach to energy-aware factory operation makes use of a probabilistic material flow simulation model. It provides information on tasks to be scheduled and executes production plans to evaluate the performance of the proposed solution. This new approach to energy-aware factory operation also provides opportunity to integrate additional ecologic criteria to improve the sustainability of manufactured products.
  • Publication
    Method for Optimizing Supply Chain Flexibility in the Production of Electrified Powertrains
    ( 2019)
    Niemann, Jens
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    Breschan, Daniel
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    Electromobility is one of the main solutions for tackling current challenges such as climate change or the scarcity of fossil resources [1]. Currently, there are large uncertainties regarding future production volumes of electric vehicles with forecast for 2025 varying between 4 % and 38% [2]-[4]. This demand volatility combined with rising importance of supply chain partners requires a fast adaptability of production volumes within the supply chain leading to a higher need of supply chain flexibility [1]. In this paper we present a method to optimize the contractual volumes between two supply chain partners coordinated by a quantity flexibility contract with fixed flexibility. Specifically, we examine whether a quantity flexibility contract fulfils its coordinating role in settings of changeable production systems. We validate our method with an example from the production of electrified automotive powertrains. The results show that we can further improve both costs and supply chain flexibility but that the coordinating role of the quantity flexibility contract is limited.
  • Publication
    Vergleichende Darstellung zweier Werkzeuge zur Simulation energetischer Aspekte in der Produktion
    Energy consideration has been a topic in simulation studies for production and logistics for some years now. The research focus has shifted recently from energy efficiency more to energy flexibility. Ever growing capacities of renewable energies from wind and sun lead to an increasingly volatile energy supply characterized by oversupply and undersupply situations and thus increasing numbers of periods with either very high or even negative electricity prices on the spot market. Energy will therefore be seen as a production factor with fluctuating availability and costs. This trend is reflected exemplarily in the two new developed simulation tools, the eniBRIC introduced in 2016 and the eFlex-Tool developed in 2018. Both tools extent the software Siemens Tecnomatix Plant Simulation and implement an energy model in addition to the actual material flow model in order to assess the energy consumption of production equipment, respectively systems. This paper intends to outline the differences and similarities as well as the designated areas of application for each implementation.
  • Publication
    Method for capacity planning of changeable production systems in the electric drives production
    ( 2019)
    Niemann, Jens
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    Market growth and technological uncertainties characterize the electro-mobility. High emission standards, fossil fuel scarcity, environmental protection, and political initiatives promote this development. Besides, factors such as customer behavior, infrastructure, new competitors, and technological developments induce high volatility in forecasted market volumes. Due to these uncertainties, production systems of electrified vehicles require a combination of changeable production systems and flexibility measures. The production capacity of changeable production systems is currently determined by a conventional capacity planning method, which does not integrate the degrees of freedom conferred by changeability. In this publication, we present a new capacity planning method of changeable production systems in electro-mobility. Changeability comprises pre-defined measures that change either the capacity or the technological spectrum of productions by an investment. A total of five changeability drivers exist, thereof we consider scalability and universality. Scalability in this context refers to the technical, local, and personnel possibilities to expand and reduce factory elements and production systems. Universality focuses on technological production properties, in particular, the ability to meet different production and technology requirements. We define specific changeability options for both drivers. Moreover, we integrate these in production capacity planning, which leads to various production configurations. Additionally, we evaluate the monetary impact and the resulting flexibility of each configuration at any time within the observation period using the real options approach. We choose this approach to integrate market uncertainties in the decision- making process. Further, a Monte Carlo simulation validates all configurations showing positive option values, and we determine a final capacity plan. We apply the method to a production system for electric drives. Our results show that an early investment in scalability and universality options improve the financial performance and flexibility of a production system in an uncertain market environment.
  • Publication
    Energieflexibilität im Maschinen- und Anlagenbau
    ( 2018)
    Stoldt, Johannes
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    Wolf, Tom
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    Büttner, Thomas
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    Langer, Tino
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    Wollen Maschinen- und Anlagenbauunternehmen ihre Wettbewerbsfähigkeit erhalten, so sind sie gefordert, sich auf die Veränderungen im Zuge der Energiewende einzustellen. Dies umfasst vor allem die Synchronisation des Energiebedarfs ihrer Produktionsprozesse mit dem marktseitigen Energieangebot. Um insbesondere mittelständische Unternehmen dabei zu unterstützen, stellt der Beitrag ein Vorgehen und weitere Hilfsmittel (u. a. einen Maßnahmenkatalog) zur Identifikation, Bewertung und Auswahl geeigneter Maßnahmen vor.
  • Publication
    Decision support for planning techniques in energy efficiency projects
    Factory operators can select from a multitude of measures to improve their energy efficiency. Despite the variety of planning techniques intended to help investigating the energy flows, little assistance is available for determining the most efficient approach to pursue in a specific project. This paper presents decision support procedures for making appropriate selections during planning, focusing on the selections of an energy model and a matching energy data acquisition method. They build on problem-independent decision models and systematize available alternatives. The models are solved independently by applying the Analytic Hierarchy Process that allows the integration and quantification of different criteria.
  • Publication
    Forschungsansätze unter Berücksichtigung der Biologischen Transformation in der Fabrik- und Produktionsplanung
    Die Auswirkungen zunehmender Produktindividualität bei gleichzeitiger Verkürzung der Produktlebenszyklen auf Entwicklung, Planung und Produktion werden im wissenschaftlichen und industriellen Umfeld vielschichtig beschrieben. Sowohl Fabrik- als auch Produktionsplanung sind dadurch mit den Anforderungen eines ständig wechselnden Produktions- und Leistungsprogramms konfrontiert. Zusätzliche Herausforderung stellen die steigenden ökologischen Anforderungen dar, die aus den Planetarischen Belastbarkeitsgrenzen resultieren. Das von der Fraunhofer-Gesellschaft ausgegebene strategische Konzept der Biologischen Transformation beschreibt die Übernahme von Funktionsweisen und Strukturen aus der Natur in die Technik unter ausdrücklicher Berücksichtigung der Nachhaltigkeit. Speziell für die Fabrik- und Produktionsplanung lassen sich aus dieser Themenkonstellation Methoden und Instrumente ableiten, mit denen diesen Herausforderungen begegnet werden kann. Die aufgedeckten und beschriebenen Potenziale dienen sowohl zur Ableitung wissenschaftlicher Forschungslinien als auch zur Konkretisierung des strategischen Konzepts der Biologischen Transformation für Fragestellungen der Fabrik- und Produktionsplanung.
  • Publication
    Requirements for volume flexibility and changeability in the production of electrified powertrains
    ( 2018)
    Niemann, Jens
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    Stoldt, Johannes
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    Büttner, Thomas
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    Eckermann, Christoph
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    Electro mobility is one way to answer the needs of the changing mobility sector. Uncertainties regarding quantities pose major challenges for the capacity planning and procurement. Current forecasts predict a share of electric vehicles between 2 % and 42 % of the whole vehicle production. This paper presents a study that intends to further the understanding of the challenges of capacity planning and the requirements of volume flexibility as well as changeability in the production and purchasing of electrified powertrains. The study relies on expert interviews of managers of the production or procurement departments of three leading German carmakers in the premium segment. The interviews were conducted using a semi-structured guide that addresses six hypotheses concerning market development, long-term capacity planning, identification and definition of courses of action, interdependencies between the production and the supplie, specifics of the production system for electrified powertrains, and access to resources. The study's results show that the volatility in the demand of electrified vehicles is expected to persist for the next 5 years. Consequently, existing demand uncertainties lead to a high number of different planning scenarios, which challenges capacity planners to provide enough capacity by relying on flexibility measures or changeability measures. Moreover, especially in the field of electro mobility, the changing supplier structure must be considered, which requires new processes of and new mindsets for automotive OEMs. Nevertheless, the task of purchasing remains vital to prevent quality losses or significant cost increases. Lastly, the supplier and the purchasing department need to be integrated in the capacity planning process. These main results implicate the need for further research and the development of a decision support system for the capacity planning of the supply chain of electric drive trains to react fast and efficient to volatile volumes.
  • Publication
    Ganzheitliche Innovation für die grüne Produktion. Ultrakurze Prozessketten und erneuerbare Energie in der Fahrzeugproduktion
    ( 2018)
    Taubert, Anne Manuela
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    Stoldt, Johannes
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    Schimang-Esche, Annegret
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    Die Verknappung fossiler Energieträger und Ressourcen stellt die politischen und öffentlichen Akteure der deutschen Produktionstechnik vor die Herausforderung, nachhaltige Systemlösungen zu entwickeln. Im E3-Konzept werden effiziente Technologien in Verbindung mit planerischen und organisatorischen Ansätzen zu synergetischen Innovationen entwickelt. Der Beitrag stellt dies ausgehend vom Beispiel einer neuen ultrakurzen Prozesskette für Komponenten von automobilen Antriebssträngen dar.