SMED

SMED stands for Single Minute Exchange of Dies. It is a phrase coined by Shigeo Shingo at Toyota Motors in the 1960s and has come to be used as a synonym for fast changeover. Shingo's 1985 book "A Revolution In Manufacturing: The SMED System" describes the theory and practice of the SMED system in detail. Anyone interested in changeover must read this book.The publisher, Productivity Press, also publishes a series of "Shop Floor" books on a variety of topics. Their "Quick Changeover for Operators" is also an excellent resource. It is a condensation and simplification of the SMED book. While it does not contain anything not Shingo's book, it may be more accessible to the associates on the shop floor. SMED was the result of a project that Toyota assigned Shingo to. Toyota realized that they needed to make more than one model car to succeed. They also realized that multiple car models meant multiple changeovers of stamping presses. Under this strategy, they could no longer live with 10-12 hour press changeovers. Shingo used standard industrial engineering techniques to analyze the changeover. His major breakthrough was in realizing that  the key to reducing changeover time was externalization of as many tasks as possible. That is, perform as much of changeover as possible with the press still running. Some examples included: Bringing the dies to the press ahead of time Assuring that the dies were complete including all fasteners Modifying all dies to the same physical size, eliminating setup adjustments Shingo also simplified the die changes: Specialized handling equipment Quick acting fasteners "T" tables These and other techniques allowed Shingo to reduce the typical press changeover from 10-12 hours to under 10 minutes. ("Single Minute" in SMED refers to single digits of minutes ie; under 10)   SMED is an excellent system and should be a significant part of any changeover reduction program. There are a couple of elements that need more development:   SMED was developed for the auto and other heavy industries. While the concepts work well in lighter industries such as packaging and assembly, it is sometimes hard to translate the ideas from one type of industry to another.    Shingo assumed that all unnecessary tasks had already been eliminated. In my experience, this is seldom the case.  I have never been on a changeover project where I did not find some tasks being done that could be eliminated.    Finally, Shingo focused on making all dies interchangeable without adjustment. Eliminating the need for adjustment is great if it can be done. Unfortunately in many industry changeover adjustment is a fact of life. If all sizes can't be "plug and play" by the use of standardized change parts, care must be taken to assure that adjustments can be made reliably and repetitively. This requires 2 steps:   First, there must be a way of measuring each setpoint. This can be position stops, digital indicators, scales or gauges.   Second, once the measuring device has been established, the correct position must be documented and available to the associate performing the setup.     So, with those caveats, I highly commend Shingo's groundbreaking work and highly recommend his book.