Quick Changeover / SMED (Single Minute Exchange of Die)
One of the most under utilized principals in Lean is the concept of Quick Changeover. "Changeover" is the time that it takes from the last good piece produced from one product to the first good piece produced (at full speed) of the next run. Why do we care about changeover time? When we are changing over from one product to another, our lead time clock is still ticking, but we are not producing parts. In Lean, this is considered waste and the type of wastes created are plentiful (waiting while we begin the next run, overproducing so that we don't starve the next process, carrying inventory "just in case", defects while we dial in the equipment to produce quality parts, motion of changing dies, etc. In the tradition of Lean, it is always our goal to reduce waste which can be done effectively by reducing the time it takes to do changeovers (or eliminate them all together). Utilizing the concepts of SMED, Shigeo Shingo's process for reducing changeover time, businesses can: