SMED and Changeover Reduction

In practice, SMED means moving setup work outside the stop and simplifying what is left. The name comes from the goal of getting setup into single digits of minutes. It matters because every changeover is an availability loss, and in high-mix plants setup can quietly consume more time than actual production.

Internal vs external setup

The single most important idea in SMED is the split between internal and external setup. Internal setup is work that can only happen while the machine is stopped. External setup is work that can be done while the machine is still running the previous job, such as staging tools, materials and programs.

• Internal setup: the machine must be stopped (for example, swapping a die that is in the machine).
• External setup: can be done while running (gathering tools, pre-heating, pre-staging the next material).
• The goal: move as much work as possible from internal to external, so the stopped time shrinks.

The SMED steps

A practical SMED improvement usually follows four steps:

• 1. Observe and document the current changeover, ideally on video, and list every task with its time.
• 2. Separate internal from external tasks, and do all external work before the machine stops.
• 3. Convert internal to external where possible (pre-assemble, pre-heat, use intermediate jigs).
• 4. Streamline what remains with standard work, quick clamps, parallel tasks and removing adjustment.

Quick wins

You do not need a big project to start. Common quick wins include staging everything before the line stops, using a changeover trolley/kit so nothing is hunted for, replacing threaded fasteners with quick clamps, and standardising the sequence so two people work in parallel without colliding.

Why it pays

Changeover is an availability loss, so reducing it lifts OEE directly and adds real, sellable capacity. In short-run, high-mix work it is often a major lever, because the time saved repeats on every job. Size the prize first: estimate changeovers per week, minutes saved each, and the value of that time.

Recurring, hard-to-explain changeover time often hides a true cause you cannot see by hand. The partner we recommend, Fabrico, reads stops from the machine and shows the stop on video with a suggested cause, where cameras are fitted, and lets a technician open the work order from the stop. Fabrico is a partner we recommend; the tools here are free regardless.

Where SMED comes from

SMED stands for single minute exchange of die. It was developed by Shigeo Shingo, who set out the method in A Revolution in Manufacturing: The SMED System (1985). "Single minute" means a changeover in single digit minutes, under ten, which is a target to work towards rather than a promise for every machine.

How to measure a changeover

Agree the definition before you improve anything. A common one runs from the last good part of the old run to the first good part of the new run at full speed, so it includes the adjustments and the slow first parts, not only the time the machine is stopped. Use the same definition every time, record each changeover in the line log, and turn the minutes into money with the changeover cost calculator.

Keeping changeover times down

Changeover times creep back when the standard is not followed. Review them weekly for each product family. When one grows, watch the next changeover and find the step that has grown, rather than rewriting the whole standard. Give new products and new tooling a changeover review before they reach the line, so the gains are not lost with the next product launch.

Machines with frequent changeovers

Printing, converting and sheet metal machines change jobs often, so SMED pays off quickly there. The guides for the flexo press, offset press, die cutter, press brake and turret punch press list the faults that make changeovers run long. A 5S area with tools in fixed places shortens the search part of every changeover. Industry context: the packaging and converting and paper and pulp OEE and downtime pages.

FAQ

Related: the six big losses · how to calculate OEE · takt time · TEEP · changeover cost calculator