Sebastian Bertsch’s research while affiliated with Leibniz Universität Hannover and other places

Due date reliability is a critical competitive factor for manufacturing companies and hence a central objective in logistics. Nonetheless, many businesses are unable to meet their own schedule reliability standards. The reasons for the insufficient achievement of logistical targets are inherent in the diverse and interdependent influential factors that affect schedule reliability. However, logistical models enable to determine these interdependencies. This paper introduces the operating curves of output lateness of a single workstation for various sequencing methods. The parameter studies comprise the preliminary work necessary to provide a complete, model-based description of production schedule deviations.

Productivity and schedule reliability are two major objectives for production areas. Companies can influence both objectives by the applied sequencing rule. While a due-date oriented sequencing rule supports the schedule reliability, a setup-time oriented sequencing rule increases productivity. Thus, a field of tension between these objectives exists in which companies have to position their production areas. To support the positioning, this paper provides a model for calculating the output lateness distribution of a production system for a setup-time oriented and a First-In-First-Out sequencing rule. Furthermore, the effect of the applied rule on productivity of production systems is analyzed.

Kurzfassung Der Plan-Abgang eines Arbeitssystems – definiert durch Plan-Termine und -Mengen – wird maßgeblich durch die Aufgaben der Losgrößenbildung sowie der Durchlaufterminierung festgelegt und besitzt als planungsrelevante Stellgröße einen erheblichen Einfluss auf das logistische Systemverhalten. Auf Basis der Verfahren der Kapazitätsabstimmung können die Schwankung des Plan-Abgangs reduziert und die Termintreue des Arbeitssystems erhöht werden. In diesem Beitrag werden ein analytisches Modell zur Beschreibung der Auswirkung einer Belastungsanpassung auf den Plan-Abgang vorgestellt und zukünftige Forschungsziele in diesem Bereich skizziert.

Enterprises are increasingly being challenged by a high diversity of variants, shortening product life cycles, and growing cost pressure. One possibility of facing these challenges is to improve the efficiency of logistics. As the borderline between a company's production with and without reference to a specific customer order, the customer order decoupling point (CODP) is a good position to significantly increase the efficiency of logistics. Apart from shortening lead times, it may also diminish the lateness at the end of the supply chain. There is currently no comprehensive analytical description of actual schedule variances within a supply chain. This paper presents a Lateness Histogram to serve as an analytical model designed to describe the mean and maximum delivery delay in a store (e.g. CODP). It is fed with the distribution of schedule and quantity variances at the store input as well as the distribution of demand at the store output. Thus, the model is another step towards analytically describing the potentials of implementing a CODP or moving it along the production process in order to obtain a possibility of quantifying the amount of lateness reduction as the CODP moves downstream. This is followed by empirical simulation studies aimed at validating the model.

Schedule compliance is one of the main logistic objectives of production systems. In order to achieve high schedule compliance, different control variables of a job shop production system can be adopted. This paper focuses on the relationship between such control variables in make-to-order processes. It provides a quantitative model to describe the effect of safety time as well as the impact of lateness distribution of the production system on schedule compliance, stock level of finished goods and delivery time. Furthermore, the applicability of this model is demonstrated by describing the results of an industry project. In this project, the model was applied to design the supply chain of a metal manufacturer to increase the capability to produce on time.

Kurzfassung Die Wandlungsfähigkeit der Produktionslogistik ist in Zeiten zunehmender Turbulenzen zu einer Schlüsselqualifikation für nachhaltigen Erfolg geworden. Um diese neuen Anforderungen an Wandlungsfähigkeit zu erfüllen, müssen bereits bei der Gestaltung der Produktionslogistik Maßnahmen vorgedacht und vorbereitet werden, mit denen auf zukünftigen Wandlungsbedarf schnell und aufwandsarm reagiert werden kann. Im Rahmen dieses Artikels wird eine Methodik vorgestellt, um auf strategischer Ebene diese erforderlichen Maßnahmen zu definieren.

Changeability of production logistics has become an important key qualification for sustainable success. In order to achieve high changeability, so called change measures have to be prepared, which enable a quick reaction to changed requirements. This article presents a concept, to plan and prepare these change measures on a strategic level.

Kurzfassung Eine hohe Wandlungsfähigkeit wird für Produktionsunternehmen vor dem Hintergrund eines dynamischen Umfelds unabdingbar. Deren zunehmende Vernetzung führt dazu, dass die Standardisierung eine essentielle Voraussetzung ist, um sich an veränderte Rahmenbedingungen anzupassen. Andererseits engen Standards den Handlungsspielraum vielfach ein. Vor diesem Hintergrund zeigt der nachfolgende Artikel, in welcher Form Standards wandlungsförderlich oder wandlungshemmend wirken.

Specialization and supply chain networking of manufacturers made standardization an essential design-concept to adapt to changing requirements. On the other hand, standardization may restrict the possible scope of action. Therefore, the following contribution discusses weather standardization may support or contradict changeability.