SMED — Single-Minute Exchange of Die — is a well-proven method for reducing the time a machine stands still during changeover. Long changeover time often leads to larger batches, more inventory and less flexibility. This guide reviews the practical steps.
Why changeover time matters more than you think
When changeover is expensive in time, you typically compensate by running larger batches. That ties up capital in inventory and makes production less flexible to changes in demand. Reducing changeover time is therefore not only a technical improvement — it changes how the whole of production can be planned.
SMED in four steps
- •Map the current changeover — observe and document each sub-element
- •Separate internal and external changeover — what can be done while the machine is running?
- •Convert internal to external — move as much as possible to while the machine is running
- •Streamline the rest — standardise and simplify the remaining internal steps
It's about standardisation
The biggest gain often comes not from technique, but from making the changeover a standardised routine everyone performs the same way. Without a standard, the changeover time depends on who is on shift — and then the improvement is fragile.
Reduced changeover time is one of the most direct routes to better availability in OEE. If you want help finding and removing the waste in the flow itself, that is precisely the core of our work with process optimisation.
✓Concrete takeaways
- →Observe a real changeover before you change anything — assumptions lead you astray
- →Move as much as possible to external changeover
- →Standardise the procedure so it doesn't depend on individuals
- →Less changeover time enables smaller batches and lower inventory
Sources and further reading
- Shingo, S. (1985). A Revolution in Manufacturing: The SMED System. Productivity Press.
- Lean Enterprise Institute — lean.org.
The references show the professional basis. Sources are reproduced in their original language.