Also called setup reduction, quick changeover, single minute exchange of dies
What is single-minute exchange of die?
A method for cutting changeover time to single digits of minutes, by moving work off the stopped machine.
What else it is called
- Other names
- setup reduction, quick changeover, single minute exchange of dies
- In French
- SMED
Related entries
Understanding single-minute exchange of die
A structured method for shortening changeovers. Every element is first recorded and sorted into internal work, which can only be done with the machine stopped, and external work, which could be done while it is still running. Most plants doing this for the first time find that between a third and a half of their changeover is external work being done internally: fetching tooling, locating paperwork, hunting for a gauge.
Moving that work out is the first and largest gain, and it costs nothing but sequence. The second stage attacks adjustment, which is usually the longest remaining block. Dies that locate on fixed stops rather than being dialled in, shims cut to known thicknesses rather than measured each time, and settings recorded rather than rediscovered are what take a changeover from thirty minutes to eight.
The reason to bother is not the time on the machine. It is that short changeovers make small batches affordable, and small batches are what shorten lead times and expose quality problems early.
In practice
Stage the next die, its tooling, its paperwork and its first-off gauges beside the press before the current run finishes. That one change is most of the first gain in nearly every plant.
Frequently asked
Do we really need changeovers under ten minutes?
The target matters less than the direction. Halving a forty-minute changeover halves the economic batch size, and most of that first halving comes from staging and standard work rather than from capital. Chase the aggressive target on the constraint and take the easy gains elsewhere.
What is internal and external work?
Internal work can only happen with the machine stopped, such as removing a die. External work can happen while it is still running, such as fetching the next die and its paperwork. The method is largely about converting the first into the second.