SMEDSMED is an acronym for Single Minute Exchange of Die, a manufacturing process that favors rapid changeovers or setups between running different machines and producing different units. It is one of the many lean production methods for reducing waste in a manufacturing process.

The origin of the concept of SMED can be traced back to the late 1950s and early 1960s in Japan. It was developed by Shigeo Shingo during the foundational years of the Toyota Production System to reduce the setup time associated with the car body molding process.

The phrase “single minute” does not imply that changeovers need to happen in just a minute, but rather that it should be completed in less than 10 minutes (single digit minute). During setups, there are activities that can be performed while the process is still running (external) and other activities that can only be done when the process has been stopped (internal). In order to reduce time, SMED focuses on making as many elements as possible external, and simplifying and streamlining all elements. There are several steps that should be considered when implementing SMED, these are:

  1. Separate internal from external setup operations.
  2. Standardize external setup activities. Ensure that everyone conducting the setup does it in the same efficient manner. Make sure that everything needed is available and in the right place. Document the whole process to ensure that it is done right.
  3. Convert (when possible) Internal to External setup activities. This can further reduce the setup time.
  4. Improve internal changeover tasks. Determine if the task can be eliminated or improved.
  5. Improve External setup tasks.
  6. Mechanize setup. Not always this step is required or justifiable, particularly if the single digit target for setup or changeover time has already been achieved.
  7. Eliminate Changeover. This is the ideal situation.

SMED is considered one of the most important tools within Lean Manufacturing that can be used by all manufacturing companies that make changeovers or setups. Its implementation requires a committed effort from within the organization since setup and changeover times can not be minimized overnight; however, those that decide to use it will benefit from:

  • Reduction of changeover and setup times in a methodological way.
  • Increase in work rate of machines.
  • Decrease of errors during changeover.
  • Facilitating the implementation of Just in Time (JIT).
  • Reduction of waste from processes.
  • Decreasing costs and increasing profit.

SMED is useful for streamlining production processes by reducing waste, removing bottleneck effects, and decreasing the inventory space required at any given time, and, in general, in making manufacturing processes flexible and more efficient.