Reducing changeover time with SMED
Single-Minute Exchange of Die (SMED) is a structured method for cutting the time to switch a line from one product to the next. It works by separating tasks that must be done while the line is stopped from those that can be prepared while it still runs, then converting and streamlining the stopped-line work.
What it is
Every product changeover stops production. SMED analyses the changeover step by step, distinguishing 'internal' tasks (only possible with the line down) from 'external' ones (doable in advance), then moves as much as possible to external and simplifies what remains, shrinking the lost-production window.
Why it is done
Long changeovers push plants toward large batches to amortise the lost time, which inflates inventory and reduces flexibility. Shorter changeovers allow smaller batches, faster response to demand and higher effective capacity — often without any new equipment, just method change.
How it is done
A changeover is filmed and broken into discrete tasks. Each is classified internal or external, and external tasks — fetching tools, pre-staging materials, pre-heating — are moved to before the stop. Remaining internal tasks are converted to external where possible, then streamlined with standardised tooling, quick fasteners and parallel work. The new method is documented and the cycle repeated.
- Film the changeover
- List all tasks
- Split internal/external
- Move work off-line
- Streamline & standardise
- Document & repeat
What to watch for
Optimising the changeover once without standardising it lets old habits return. Focusing only on speed while ignoring first-pass quality after restart trades one loss for another.
Related practices
Optimising clean-in-place (CIP)
Running a process capability study
Setting up an OEE measurement programme
Related topics
SMED (Single-Minute Exchange of Die) · Value Stream Mapping (VSM) · Takt Time
Common in: Food Processing · Pharmaceuticals · Paper & Packaging · Brewing & Beverage · Dairy