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Item type:Publication, Access status: without files , Concept of manufacturing control for a workstation with sequence-dependent setup times in a make-to-stock productionSequence-dependent setup times pose a challenge for a make-to-stock production. If companies apply setup-optimised sequencing to reduce setup efforts, varying replenishment times of the finished goods warehouse will increase the required safety inventories of the products. This publication presents a comprehensive manufacturing control concept for workstations with sequence-dependent setup times in make-to-stock production. The manufacturing control concept aims to effectively control the workstation and finished goods inventory, thereby enhancing the achievement of logistical objectives. The proposed concept integrates three relevant tasks of manufacturing control: order generation, capacity control, and sequencing. Cumulative Production Figures serve as a superordinate procedure, facilitating order generation and capacity control, while cyclical sequencing reduces setup efforts. Simulation experiments validate and evaluate the manufacturing control concept, demonstrating its effectiveness in managing setup efforts while limiting the negative impacts on required safety inventories. The results align with theoretical modeling and show potential for practical application in companies with make-to-stock production.Publicationtype: Conference Paper50 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Assessing the impact of cyclical sequencing in make-to-stock production with sequence-dependent setup timesCyclical sequencing is a well-known sequencing method in which the sequence of products is repeated cyclically. In make-to-stock production with sequence-dependent setup times, cyclical sequencing influences important logistical objectives in production as well as in the finished goods warehouse. We derive a simple model that enables companies to set the important parameters consistently. In simulation experiments, the model is validated for its influence on logistical objectives such as capacity requirements in production and mean finished goods inventories in the warehouse.Publicationtype: Conference Paper22 28 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , The strong effect of flexible capacities on achievable WIP levels and throughput times : a simple model and its implicationsSetting WIP levels at the workstations of a production is an important task: WIP levels affect throughput times as well as utilisation rates. Consequently, they also impact the delivery times to customers and the productivity. Queueing theory provides profound knowledge regarding the factors for determining suitable WIP levels. However, the existing models have been neglecting the important influence of capacity flexibility. This paper suggests an extension of the well-known Kingman equation to model the impact of flexible capacities on the required WIP levels. Simulation experiments have shown that the model is able to accurately forecast the utilisation level of a workstation for different factor levels of capacity flexibility, WIP and load variance. Companies can use the model to set consistent target levels for these factors.Publicationtype: Journal Article14 107 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Status Quo on Production Planning and Control(publish-Ing, 2024-12); ; ; ; What is the status quo in production planning and control (PPC)? This question is the recurring basis for the PPS Report, which has now been initiated for the sixth time by the following four German institutes in the field of production technology: Institute of Production Systems and Logistics (IFA) at Leibniz Universität Hannover, Institute of Production Management and Technology (IPMT) at Hamburg University of Technology, Laboratory for Machine Tools and Production Engineering (WZL) at RWTH Aachen University and Fraunhofer Institute for Casting, Composite and Processing Technology (IGCV). The aim of this survey is to regularly establish a picture of current approaches and challenges companies face in relation to PPC. The current report focuses on the areas of data collection, logistic objectives and sustainability in PPC. The results of the report show the approaches and challenges of the companies surveyed in achieving logistic objectives, such as schedule reliability, and in digitization, especially with regard to collecting and using data from production processes. Furthermore, the report highlights the challenges that prevent companies from implementing a circular economy, namely high complexity and uncertainty. Additionally, the report addresses how companies deal with high and volatile energy prices, which most of the companies surveyed have not yet taken into account in their PPC.Publicationtype: Journal Article40 39 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , PPS-Report 2023: Studienergebnisse(Werkzeugmaschinenlabor WZL der RWTH Aachen University, 2023-12); ; ; Karg, FlorianDer diesjährige Report zum Thema Produktionsplanung und -steuerung bietet umfassende Einblicke in die Perspektiven produzierender Unternehmen und somit in aktuelle Entwicklungen in der Produktionsplanung und -steuerung. Im Vordergrund stehen dieses Jahr die gesellschaftlich und politisch relevanten Themen der Kreislaufwirtschaft und der Energieversorgung sowie der Zuverlässigkeit der PPS und Nutzung von Produktionsdaten. Weiterhin sind die Termineinhaltung für Auftragsfertiger und der Servicegrad für Lagerfertiger eine Herausforderung für produzierende Unternehmen. Der größte negative Einfluss auf die Termineinhaltung und den Servicegrad ist die Materialverfügbarkeit. Weitere negative Einflüsse sind vielfältig. Die Verbesserung der logistischen Zielgrößen kann durch Anwendungen der Digitalisierungen verfolgt werden. Die dazu erfassten Maschinendaten werden jedoch noch nicht vollständig ausgewertet, was auf das Fehlen personeller Ressourcen und der technischen Komplexität zurückzuführen ist. Im Themengebiet der Kreislaufwirtschaft sehen die befragten Unternehmen die größte Herausforderung bei der Umsetzung in der Wiederaufbereitung. Zudem stellt die zu geringe Datenqualität ein Hindernis für die zirkuläre Wertschöpfung dar. Trotz der aktuellen Energiekrise gaben die Unternehmen eine nur geringe Relevanz für die Berücksichtigung von kurzfristigen Energiepreisschwankungen an. Ursächlich dafür ist hauptsächlich die mangelnde Flexibilität in der Produktion. Jedoch bewerten drei von vier Unternehmen die Relevanz von Energieautarkie als mindestens mittelmäßig und eins von drei Unternehmen plant, in regenerative Eigenerzeugungsanlagen zu investieren.Publicationtype: Report109 191