SMED refers to the theory and techniques used for the reduction of equipment setup times. SMED has as its objective to accomplish setup times in less than ten minutes, i.e. a number of minutes expressed by a single digit. Although not all setups can be literally reduced to this time, between one and nine minutes, this is the goal of the SMED methodology.
SMED is based on the concept of the mudas removal, as reduction in time of changing over from one die to another is a saving in non-value adding process time. Lowering the change over time also results low inventories due to shorter runs thus, a saving in the inventory is also made available. SMED is also often called as Quick Changeover (QCO).
SMED was developed by Shigeo Shingo over a period of almost 20 years. The development involved intensive study and improvement of setup operations in many factories and industries. It was facilitated by the recognition that set-up operations can be categorized as
- Internal Setup – Machine must stop to perform the operation
- External Setup – Machine can be kept running whilst operations performed
Shigeo Shingo recognizes eight techniques that should be considered in implementing SMED.
- Separate Internal from External setup operations
- Convert Internal to External setup
- Standardize function , not shape
- Use functional clamps or eliminate fasteners altogether
- Use intermediate jigs
- Adopt parallel operations
- Eliminate adjustments
- Mechanization
