SMED: How to Reduce Changeover Time
SMED (Single-Minute Exchange of Dies) shrinks the time a line is stopped between products. It works in three phases — here is how to apply each, step by step.
The three phases of SMED
- 1
Separate internal and external setup
List every changeover step and classify it: internal (must be done while stopped) or external (can be done while running). Just moving external work out of the stoppage often cuts changeover time ~30% with no equipment changes.
- 2
Convert internal to external
Redesign steps so more can be done while the machine still runs — pre-heat tools, pre-stage dies, pre-kit parts — shrinking the stopped window further.
- 3
Streamline the remaining elements
Speed up what is left: quick-release clamps instead of bolts, standardised settings instead of adjustments, organised tool placement, and parallel work by more than one person.
Frequently asked questions
What does the 'single minute' in SMED mean?
The goal of getting changeover into single-digit minutes (under ten). It is a target, not a promise — but the method routinely cuts changeover time by 50–80%.
What is internal vs external setup?
Internal setup must happen while the machine is stopped; external setup can happen while it runs. The first SMED win is moving as much as possible from internal to external.
Where do I start?
Record one changeover, list and time every step, then classify internal vs external. That single act usually reveals 30%+ that can move outside the stoppage immediately.
Related lean tools & guides
Break the changeover down on video
Yamazo Studio's SMED track splits a changeover into internal/external steps from video and flags what can move external — offline.
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