Analysis and Improvement of Multiproduct Bernoulli Serial Lines: Theory and Application

This paper is devoted to the performance analysis and continuous improvement of multiproduct manufacturing systems. First, a Bernoulli model of multiproduct serial line with unreliable machines and finite buffers is introduced. In such a model, each machine is capable of processing multiple product types, and each buffer is shared for all products. Closed formulas have been derived to evaluate the production rate of the line with one or two machines, and recursive procedures are used to analyze longer lines. Numerical studies indicate that such a method has a high precision in performance evaluation. The system-theoretic properties, such as asymptotic property, monotonicity, and reversibility, have been investigated. Second, in order to improve system performance, bottleneck (BN) analysis has been carried out to identify the machine and product whose improvement will lead to the largest improvement in the system production rate. Various types of BNs have been defined, and the BN indicators, based on the data collected on the factory floor, are proposed to identify the BNs without the complicated calculations of the production rate and its sensitivities. Numerical experiments have justified the practical usefulness of such indicators for BN identification in multiproduct manufacturing systems. Finally, a case study is introduced to illustrate the applicability of the model and the method.