Unpaced production lines with three simultaneous imbalance sources

Purpose – The purpose of this paper is to investigate the performance of unpaced reliable production lines that are unbalanced in terms of their mean operation times, coefficients of variation and buffer capacities. Design/methodology/approach – Simulations were carried out for five‐ and eight‐station lines with various buffer capacities and degrees of means imbalance. Throughput, idle time and average buffer level performance indicators were generated and statistically analysed. Findings – The results show that an inverted bowl allocation of mean service times, combined with a bowl configuration for coefficients of variation and a decreasing order of buffer sizes results in higher throughput and lower idle times than a balanced line counterpart. In addition, considerable reductions in average inventory levels were consistently obtained when utilizing a configuration of progressively faster stations, coupled with a bowl‐shaped pattern for coefficients of variation and an ascending buffer size order. Research limitations/implications – The results for these specific experiments imply that resources expended on trying to achieve a balanced line could be better used by seizing upon possible enhanced performance via controlled mean time, variability and buffer imbalance. Results are valid for only the line type and parameter values used (simulation results are specific and not general). Practical implications – Guidelines are provided on design strategies for allocating labour and capital unevenly in unpaced lines for better performance in terms of increased throughput or lowered idle time or average buffer levels. Originality/value – This paper might be viewed as one of the first simulation investigations into the performance of unpaced production lines with three sources of imbalance.