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The quick‐changeover tool can be used to reduce or eliminate waiting waste and increase machine availability. In manufacturing, maintenance must change over a line when it is switched from making one product to the next. If a manufacturing plant can achieve shorter changeover times, it can run its production line with smaller batches. This reduces inventory waste and allows the plant to match its production output to customer demand. If a plant spends more time producing and less time changing over, it can increase its capacity.

Dr. Shigeo Shingo developed quick‐changeover techniques while working with an auto manufacturer. He defined changeover time as the total time from the last unit of production to the first unit of good production at full speed. To dramatically reduce changeover time, teams convert internal work to external work.

Internal work consists of all the tasks performed while the line is shut down. External tasks are performed either before the line is shut down or after the line is up and running again. By performing a detailed work breakdown, the team can convert internal tasks to external task: doing things ahead of time, or after the fact, so that the actual downtime and internal work are minimal.

Unlike other tools used in Lean, quick changeover may require some significant capital investment, such as specialty tools and fasteners designed to minimize downtime. The goal is to re‐design, re‐engineer, and re‐tool.