Design of a flexible assembly line to control the bottleneck

Abstract

In this paper, a methodology for the design of a flexible assembly line system (e.g. a flow shop consisting of a set of tandem flexible workstations, a set of automated inspection stations, a loading station, and an unloading station, linked by a material handling system) is presented, while controlling the bottleneck problem. This paper is a generalization of earlier work, where a design strategy for a simplified version of a similar manufacturing system was proposed. In this paper, the loading process is stationary with identically distributed interarrival times, and defective work-pieces are reprocessed at the corresponding workstations. Here, the performance of the assembly line is modelled by a non-Markovian queueing network with finite capacity queueing nodes. Based on this queueing network, a stochastic optimization model is then presented to select the minimum required local storage sizes of the workstations and the transporter stations such that the resulting probabilities of finding each workstation and each transporter station blocked (e.g. full) are sufficiently close to zero. To solve the proposed optimization model, a heuristic algorithm is then developed. Finally, an example is presented, and the relative accuracy of the proposed algorithm is investigated by a simulation study.