Manufacturing execution: Theory and concepts

Modern theory of manufacturing execution holds that time is the most telling indicator of manufacturing performance, that by systematically reducing the manufacturing interval and its variation, a manufacturer can follow a proven path to world class status. Because the method is based on a different philosophy of manufacturing operations, rather than on expensive technology, it requires little initial capital investment. The role of variation is emphasized in this paper, and a quantitative analysis of variation shows how variability occurs in the factory. Batching, quality problems — including low yield — and unreliable equipment and material flows are shown to be major sources of variation and delay. The roles of factory loading, load smoothing, and flexible manufacturing are also shown in quantitative terms. Practical suggestions are given for implementing JIT (just-in-time), including kanban and pull systems, lot sizing and setup time reduction, and compensating for losses from low yields to make JIT work.