SMED : Formal Method

There are seven basic steps to reducing changeover using the SMED system:

1. OBSERVE the current methodology

2. Separate the INTERNAL and EXTERNAL activities. Internal activities are those that can only be performed when the process is stopped, while External activities can be done while the last batch is being produced, or once the next batch has started. For example, go and get the required tools for the job BEFORE the machine stops.

3. Convert (where possible) Internal activities into External ones (pre-heating of tools is a good example of this).

4. Streamline the remaining internal activities, by simplifying them. Focus on fixings - Shigeo Shingo rightly observed that it's only the last turn of a bolt that tightens it - the rest is just movement.

5. Streamline the External activities, so that they are of a similar scale to the Internal ones.

6. Document the new procedure, and actions that are yet to be completed.

7. Do it all again: For each iteration of the above process, a 45% improvement in set-up times should be expected, so it may take several iterations to cross the ten minute line.

The SMED concept is credited to Shigeo Shingo, one of the main contributors to the consolidation of the Toyota Production System, along with Taiichi Ohno.