The performance of unpaced production lines with unequal operating time variabilities and buffer sizes

This paper investigates the behaviour of unpaced production lines that are imbalanced with respect to both their work time coefficients of variation and buffer sizes. The lines were simulated with varied values of line length, buffer capacity and patterns of imbalance. Using a range of statistical methods, idle time and average buffer level (ABL) output data were analysed and compared to a balanced line counterpart. Various conclusions concerning the relationships among the exogenous and endogenous variables were made. The best pattern in terms of idle time was identified to be a bowl-shaped coefficient of variation configuration, combined with a buffer arrangement whereby more buffer capacity is concentrated at the beginning of the line. In terms of ABL, the superior pattern turned out to be a bowl-shaped coefficient of variation order, together with a buffer arrangement under which the buffers are concentrated towards the end of the line.