Abstract As a common production practice in many developing economies and in reverse logistics, unbalanced merging assembly lines are a research area which is re-emerging in prominence. This paper aims to study the performance of reliable, unpaced merging assembly lines that are unbalanced in terms of their buffer storage sizes. Lines are simulated with different values of line length, mean buffer storage capacity and configuration of uneven buffer allocation. The best patterns in terms of generating higher throughput and lower average buffer level as compared to a balanced merging line are those where total available buffer capacity is allocated as evenly as possible between workstations and to concentrate more buffer capacity towards the end of the line, respectively.
