Definition:
Existing systems and tools often need to be reinvented to support working in smaller batches. Shigeo Shingo created concept of SMED (Single-Minute Exchange of Die) in order to enable a smaller batch size of work in early Toyota factories.
SMED (Single-Minute Exchange of Die) is a system for dramatically reducing the time it takes to complete equipment changeovers. The essence of the SMED system is to convert as many changeover steps as possible to “external” (performed while the equipment is running), and to simplify and streamline the remaining steps. The name Single-Minute Exchange of Dies comes from the goal of reducing changeover times to the “single” digits
Further Reading:
Book: The Lean Startup – by Eric Ries