Glossary
SMED full form: Single-Minute Exchange of Die, explained
SMED stands for Single-Minute Exchange of Die — a method for cutting changeover time down to single digits, by moving setup work out of the stopped-machine window.
Updated October 2026 · ThingConnect team
Internal setup vs external setup
SMED's entire method comes down to one split. Internal setup is work that can only happen with the machine stopped — swapping a fixture, pulling a tool, dialing in an offset. External setup is everything that can be done while the machine is still running the previous job — staging the next tool, pre-setting an offset on a second holder, pulling the next program up.
Most changeovers, left alone, treat almost everything as internal by habit — the operator starts looking for the next tool only after the machine stops. SMED’s move is just forcing that question: for each step in the changeover, does it actually require the machine to be stopped, or has it always been done that way?
A worked example
A changeover that currently runs 45 minutes, broken into its real steps:
- 12 min — walk to the tool crib, find the next tool set
- 18 min — remove old fixture, mount new fixture
- 10 min — dial in offsets, run first-off
- 5 min — paperwork, program selection
Moving the tool search and paperwork to before the machine stops — while the previous job is still running — removes 17 minutes without touching the physical fixture swap at all. 45 minutes becomes 28 from reclassification alone, before any work on the fixture-swap step itself.
Questions
Frequently asked questions
SMED stands for Single-Minute Exchange of Die — a lean manufacturing method, developed by Shigeo Shingo at Toyota, for reducing equipment changeover time to under ten minutes (ideally a single digit).
Internal setup is anything that can only be done while the machine is stopped — removing a fixture, changing a tool. External setup is anything that can be prepared while the machine is still running the previous job — staging the next tool, pre-setting an offset. SMED's core move is converting as much internal setup to external as possible.
Changeover time is counted against Availability in an OEE calculation — a long changeover is unplanned (or under-planned) downtime. Shortening changeover through SMED is one of the more reliable ways to move the Availability component without touching cycle time or scrap at all.
Yes — the name comes from stamping press die changes, but the same internal/external split applies to any CNC changeover: tool changes, fixture swaps, program loads, and first-off approval. The method generalizes; the name stuck from where it started.