SMED
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SMED (Single-Minute Exchange of Die) is a systematic approach to reducing changeover time to under ten minutes.
Definition
SMED (Single-Minute Exchange of Die) is Shigeo Shingo's systematic methodology for dramatically reducing equipment changeover time—ideally to single-digit minutes (under 10 minutes). SMED classifies changeover activities as internal (requiring machine stoppage) or external (possible while machine runs). The method converts internal activities to external, streamlines remaining internal activities, and eliminates unnecessary activities. By slashing changeover time, SMED enables smaller batches, better flow, and more flexibility without sacrificing capacity.
Examples
A stamping press required 4 hours to change dies. SMED analysis revealed that 60% of the time was external work (finding tools, locating dies, paperwork) done with the machine stopped. By completing external work beforehand and streamlining internal work with quick-release clamps and pre-positioned dies, changeover dropped to 12 minutes.
Key Points
- Separate internal work (requires stoppage) from external work (can happen while running)
- Convert internal to external wherever possible
- Streamline remaining internal work through parallel operations and quick-change devices
- Challenge and eliminate unnecessary changeover activities
Common Misconceptions
SMED requires capital investment. Many SMED gains come from procedural changes—doing work in parallel, preparing in advance, organizing tools. While quick-change devices help, significant improvement often requires little investment.
SMED only applies to manufacturing equipment. Any process with changeover between work types can apply SMED principles—service transitions, system processing, room turnovers.