ABSTRACT
We consider a discrete-part production line consisting of two machines with random processing and failure times. One option that can mitigate the effect of these uncertainties is the installation of a buffer between the two machines to avoid starving and blocking of the machines. In this article, we additionally allow the keeping of spare parts in stock to enable a fast repair and reduce machine downtime.
We introduce a new model to support the optimization of the buffer size and the spare parts inventory level simultaneously. The model is based on a continuous-time Markov chain and our aim is to minimize the average costs, which are composed of costs for work in process and the stock-keeping of spare parts, subject to a minimum target throughput.
Our numerical analysis reveals that the availability of spare parts can increase throughput enormously or reduce the required buffer size for a given target throughput. Using our approach, as opposed to a sequential approach, we can quantify the cost savings, which can be obtained by a joint optimization of the buffer size and the inventory level. Large cost savings can be obtained by the application of our new approach.
Additional information
Notes on contributors
Gudrun P. Kiesmüller
Gudrun P. Kiesmüller holds the chair of operations management at the Otto-von-Guericke University in Magdeburg (Germany). She obtained her Ph.D. in mathematics from the Julius-Maximilans University in Würzburg (Germany) and was working as a postdoc and an assistant professor at the Technical University Eindhoven (The Netherlands) before she was affiliated as a professor for supply chain management at the Christian Albrechts Universität zu Kiel (Germany). Her main research interests are related to stochastic modeling in after-sales service, inventory control, and supply chain management.
Julia Zimmermann
Julia Zimmermann is a Ph.D. candidate at the chair of operations management at the Otto-von-Guericke University in Magdeburg, Germany. Her current research topic is the design of manufacturing systems with spare parts provisioning.