The Quick-Change-of-Die (SMED) system is a systematic approach designed to reduce die or tooling changeover time to single-digit minutes or even less. It is a key supporting technology in modern lean manufacturing systems. Its core objective is to minimize equipment downtime and improve production line flexibility through process optimization and standardized operations, adapting to the market demands of multi-variety, small-batch production.
This system originated from the Toyota Production System practices of the 1950s and has been systematically refined into a replicable methodology. The implementation process typically involves four stages: First, mold changeover operations are categorized into internal operations (which must be completed while the equipment is stopped, such as disassembling the old mold and hoisting the new mold) and external operations (which can be prepared in advance while the equipment is running, such as tool inventory and material pre-positioning). Second, through modular tooling design, unified positioning benchmarks, and the application of rapid clamping mechanisms, internal operations are converted into external operations as much as possible. Subsequently, motion analysis and parallelization improvements are performed on the remaining internal operations to eliminate redundant steps. Finally, standardized operating instructions and visual management are established to ensure the stability and repeatability of the mold changeover process.
Rapid mold changeover systems not only significantly reduce non-value-added downtime losses but also improve equipment utilization and production response speed, helping companies achieve product switching and order fulfillment at a lower cost. In fields such as injection molding, stamping, die casting, and metal processing, its application has become an important indicator for measuring the flexibility and lean manufacturing level of manufacturing enterprises, and it has positive significance for promoting intelligent manufacturing and the construction of efficient supply chains.
