Changeover
Changeover is the time it takes to go from the last good part of one product run to the first good part of the next product run. Quick changeover is critical to Lean. It provides the flexibility to match the product mix to actual demand.
In turn, this prevents the accumulation of inventory that can add cost and substantial waste to a value stream.
Watch out for a terminology issue with this term. Setup and changeover are sometimes used interchangeably. In other cases, setup is viewed as a component of changeover. In that usage, it refers to the part of the transition that is focused on configuring a machine for a different product type.
In most cases, however, it suffices to use the terms interchangeably. Regardless of how you use these Lean terms, though, you will likely see the term “setup reduction” rather than “changeover reduction”.
For perspective on the choice of terms, neither Taiichi Ohno (Toyota Production System: Beyond Large-Scale Production) nor Shigeo Shingo (The Sayings of Shigeo Shingo: Key Strategies for Plant Improvement) list “changeover” in their indexes. Both have setup listed.
I recommend using the term “changeover” when talking about switching between products, and “setup” when focusing on what is going on with the machine or process.
Office Changeover
Changeover is present in the office as well as on the shop floor. In fact, Lean offices often need to focus their waste reduction efforts on setup reduction to improve flow. For example, it can take several minutes to open up the programs and find the proper file folders to switch from task A to task B. That time is changeover.
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