Definition
The method of compressing the change of time from hours to less than 10 minutes makes it possible for small batch production and rapid response to changes in demand.
In detail
SMED separates internal operations that require a shutdown from external operations that can be done while the machine runs, then converts and simplifies steps to shrink changeover downtime as much as possible. It addresses the problem of long changeovers forcing large-batch production. Unlike wheel-level scheduling arrangements, SMED focuses on the changeover actions themselves; after improvement, batch size, production frequency, replenishment, and lead time should be reassessed to verify quality and delivery. The acceptance line is changeover time below takt time, or an improvement of 50% or more (either one qualifies); "single-minute" is where the method's name comes from and the direction to aim for, not the acceptance line — whether 15 minutes is good enough depends on takt time.
Example in practice
A stamping plant has an average changeover time of 2 hours, leading to large batches and high inventory. Through SMED improvement, separating internal operations (done during downtime) from external operations (prepared before downtime) and optimizing fastening methods, changeover time is reduced to 15 minutes. As a result, small-batch production is possible, inventory decreases, and response to customer orders is faster.