Manufacturing & production
SMED and quick changeover: cutting setup time on the production floor
How to apply SMED to reduce changeover time: measure the current setup, separate internal and external work, convert, streamline and standardize, with an example.
A changeover is the time between the last good unit of one product and the first good unit of the next: changing molds, dies, flavors, sizes, labels or settings. Long changeovers push plants to run large batches, which means more inventory, less flexibility and longer customer lead times. SMED (single-minute exchange of die) is a structured method for cutting changeover time, often dramatically, usually with simple changes rather than new machines.
Internal vs. external work
The core idea of SMED:
| Type | Definition | Example |
|---|---|---|
| Internal work | Can only be done while the machine is stopped | Removing and mounting the mold |
| External work | Can be done while the machine is still running | Fetching the next mold, preheating it, preparing tools and materials |
Most changeovers include external work being done while the machine waits. Moving it outside the stop is the fastest win.
The SMED steps
- Measure the current changeover. Video it, list every step with times, from last good unit to first good unit.
- Separate internal and external steps.
- Convert internal steps to external where possible (preheat molds, preset tools, pre-stage materials).
- Streamline the remaining internal steps (quick-release clamps, standard heights, fewer bolts, parallel work by two people).
- Streamline external steps too (organized tool carts, checklists).
- Standardize the new method with a checklist and train everyone (process management and SOPs).
Example: injection molding changeover
| Step | Before (min) | After (min) | Change |
|---|---|---|---|
| Find and bring next mold | 15 | 0 | Done before the stop, mold staged at the machine |
| Remove current mold | 15 | 10 | Quick-release clamps |
| Mount new mold | 20 | 12 | Standard mounting height, pre-set locators |
| Connect water and heaters | 10 | 5 | Quick connectors |
| Preheat mold | 15 | 0 | Preheated externally |
| Adjust settings and first parts | 15 | 8 | Standard setup sheet (mold management) |
| Total | 90 | 35 |
Changeover dropped from 90 to 35 minutes, mostly from organization and preparation.
Why it matters
- More capacity: saved changeover time becomes production time (machine downtime tracking)
- Smaller batches: lower inventory and faster response to customers (make-to-order vs. make-to-stock)
- Less startup scrap when settings are standardized (scrap and rework tracking)
- Better OEE through higher availability (OEE and production KPIs)
Running a SMED project
- Pick the machine where changeovers cost the most time
- Involve operators and technicians who do the changeover
- Video and time the current method
- Implement quick wins first (external preparation), then equipment changes
- Measure several changeovers after the change to confirm the gain
- Spread the method to other machines
A SMED effort works well as a Kaizen event (Kaizen).
Tracking changeovers
Record each changeover's start, end and product pair in the production records. Track average changeover time per machine and the share of production time lost to changeovers, and review it weekly.
Where Cirquolus fits
The Cirquolus production management system records production on the floor with productivity and performance monitoring and mold records, and the Business Compass improvement portfolio includes Kaizen and Lean workspaces for changeover projects.
Frequently asked questions
What is SMED?
Single-minute exchange of die: a method for reducing changeover time by separating, converting and streamlining setup steps.
What is the difference between internal and external setup?
Internal setup can only be done when the machine is stopped. External setup can be done while it is still running.
How much can SMED reduce changeover time?
Results vary, but large reductions are common when external work is moved outside the stop and remaining steps are streamlined.
Is SMED only for molding and stamping?
No. It applies to any changeover, including food lines, packaging, printing and labeling.
Bring this workflow to a Cirquolus demo.
Show us your current process, companies and branches. We will map it to the modules you need and propose a realistic rollout.