Throughput assessment of mixed-model flexible transfer lines with unreliable machines

Most of the research that has been carried out to date to analyse transfer line performance is so far limited to the mono-product systems due to the complexity associated with multi-product considerations. In this paper, we consider mixed-model flexible transfer lines manufacturing several product types. The flexible transfer line workstations are arranged in a serial configuration, interconnected by an automatic transfer mechanism, and subject to operation-dependent failures. The throughput is an important tool for measuring the performance of transfer lines, and this paper establishes a method for assessing this throughput. A general simulation model is proposed, allowing a comparison of the performance of the proposed method with those of approximate existing techniques. Numerical computations show that the proposed formulae are robust to estimate the throughput of multi-product transfer lines, and that the results are very satisfactory.