In this paper we study the operating behaviour and performance of reliable, unpaced and unbalanced serial production lines with either imbalanced service time means, unequal coefficients of variation, or uneven buffer capacities. The lines were simulated with various values of line length, buffer storage size, degree of imbalance, coefficient of variation, along with a number of imbalance configurations. The primary measures of efficiency were idle time and average buffer level. Output data from the discrete event simulation of such lines under their steady-state mode of operation were analyzed using a set of statistical methods. Various relationships between the independent and response variables, rankings of configurations and comparisons with balanced lines were obtained. For the mean processing times imbalance, it turned out that a bowl-shaped arrangement provides smaller idle time amounts and lower average buffer levels than those of a balanced line counterpart. As regards the variability imbalance, it was found that the best configurations are respectively, a bowl allocation and a monotone decreasing order, with the first resulting in decreased idle times and the second leading to lower average buffer levels than those of a balanced line. As far as the buffer size imbalance is concerned, it was concluded that the most advantageous patterns that generate lower idle times and average buffer levels as compared to a balanced line are to respectively distribute total available buffer capacity as evenly as possible along the buffers and to allocate more buffer capacity towards the end of the line.
