Asymmetrical buffer allocation in unpaced merging assembly lines

- Simulation suggests that line imbalances can be managed to improve performance.
- Lines vary on length, mean buffer storage capacity and buffer configurations.
- Modifications to total buffer capacity produce higher throughput.
- Modifications to total buffer capacity produce lower average buffer levels.
- Higher buffer capacity should be concentrated toward the end of the line.

Asymmetrical merging assembly lines are a research area which is rising in prominence due to increasing use in reverse logistics, remanufacturing, and developing economies. This paper studies the performance of reliable, unpaced merging assembly lines with asymmetric buffer storage sizes. Lines are simulated with varying line lengths, mean buffer storage capacities and uneven buffer allocation configurations. Contrary to typical manufacturing expectations, results indicate that production line imbalances do not always result in detrimental performance. Higher throughput and lower average buffer levels, as compared to a balanced merging line, are found where total available buffer capacity is allocated as evenly as possible, and with a higher buffer capacity concentration towards the end of the line. This paper contributes to total production line knowledge by providing performance improvement methods for unpaced merging assembly lines with asymmetrical buffer allocation, and inexpensive or no cost managerial options to increase productivity and resource utilization, and decrease waste, in asymmetrical merging assembly lines.