A system-theoretic property of serial production lines: improvability

A production system is described as improvable if the limited resources involved in its operation can be redistributed so that a performance measure is improved. In this paper the property of improvability is analysed for the case of a particular system, the serial production line. Improvability of the production rate with respect to machine efficiency and work-in-process distribution is analysed, appropriate indicators of improvability are derived, and their utilization in the process of continuous improvement is discussed. It is shown, in particular, that in a well-designed system each buffer is on average half-full, and each intermediate machine has equal frequencies of blockages and starvations