What is the difference between internal and external changeover work?

Internal work can only be done with the machine stopped, such as removing one die and fitting the next. External work can be done while the machine is still running, such as fetching tools, staging material or preheating the next die. SMED moves as much work as possible from internal to external.

How do you measure changeover time?

From the last good part of one product to the first good part of the next, so adjustments and trial runs count. Only internal work adds to the changeover time; external work done while the machine runs does not.

How many changeovers should I study?

Start with one representative changeover on the machine where changeover time costs the most. Once you have a new standard, time a few more changeovers on different shifts to check that everyone follows it.

What does SMED stand for?

Single-minute exchange of die. Single-minute refers to the goal of a changeover that takes a single-digit number of minutes, under ten. It is a direction to work toward: any internal minutes removed free up machine time.

Should I use the Excel or the PDF version?

Print the PDF to take to the machine on a clipboard while you observe. Type the results into the Excel version afterwards: it adds up the internal and external time before and after and works out the time saved.

Free template

SMED changeover worksheet

A SMED changeover worksheet is the form you use to break one changeover into its steps, time each one and mark it internal (only possible with the machine stopped) or external (possible while it runs). This one adds a column for whether each internal step could move to external, one for the improvement idea, and before and after totals, so you can see how much shorter the changeover could be. Changeover time is the internal total, measured from the last good part of one run to the first good part of the next.

Free to use: print it, copy it and edit it for your team. Enter your name and work email once to download.

Page 1 of the SMED changeover worksheet: header fields for machine, change from and to, date and observer, and a numbered step table with time, internal or external, move to external, improvement idea and after columns. — Step list with timesInternal / externalMove to external?Improvement ideasBefore and after totals

When to use it

When to use a SMED worksheet

Before a SMED workshop, to record today's changeover as the baseline.
On the bottleneck machine, or any machine where long changeovers force large batches.
After improvements, to compare the new changeover with the old one and write the new standard.

How to fill it in

1
Fill in the header
The machine or line, the product you are changing from and to, the date and the observer.
2
Observe or film one changeover
Time it from the last good part of the old run to the first good part of the new one. Filming makes it much easier to split into steps afterwards.
3
List every step with its time
Write the steps in order with their time in minutes. Include walking, searching and waiting: they are steps too.
4
Mark each step internal or external
I if the machine must be stopped, E if it could be done while it runs, based on what happens today.
5
Ask whether each internal step can move
Could it be done before the stop or after the restart? Mark Y or N in the move to external column.
6
Write an improvement idea
For each step you can move, shorten or remove: prepare tools and material in advance, preset settings, use quick-release clamps, standardize heights.
7
Fill in the after columns and compare
Enter the new classification and expected time. The Excel version defaults moved steps to external, adds up internal and external time before and after, and shows the time saved.

A filled-in example

Illustrative, not a benchmark

A press changeover with 90 minutes of internal work and 20 minutes of external work.

Six internal steps, 30 minutes in all, could move to external: fetching the next die, finding clamps, preheating and preparing first-off paperwork.
A quick-release clamp idea could cut die fixing from 12 minutes to 4.
After: internal time 90 − 30 − 8 = 52 minutes, external time 20 + 30 = 50 minutes.

The changeover drops from 90 to 52 minutes, 42% shorter. To turn the minutes saved into capacity or smaller batches, use the SMED changeover calculator.

Common mistakes

Timing from memory or the schedule
Observe or film a real changeover. Estimates miss the waiting and searching.
Leaving out walking, searching and waiting
They are often the easiest minutes to remove.
Marking steps as they should be
Record what happens today in the first columns. The after columns are for what should happen.
Buying hardware before moving work
Move internal work to external first. It usually costs little compared with new tooling.
Not writing down the new sequence
Without a standard, the next shift goes back to the old way.

Download the template

Free to use: print it, copy it and edit it for your team. Enter your name and work email once to download.

Do this in LeanSuite

LeanSuite watches a video of your changeover, separates internal and external tasks, and recommends a leaner sequence with the projected time saved.

SMED changeover worksheet

When to use a SMED worksheet

How to fill it in

Fill in the header

Observe or film one changeover

List every step with its time

Mark each step internal or external

Ask whether each internal step can move

Write an improvement idea

Fill in the after columns and compare

A filled-in example

Common mistakes

Timing from memory or the schedule

Leaving out walking, searching and waiting

Marking steps as they should be

Buying hardware before moving work

Not writing down the new sequence

Download the template

Do this in LeanSuite

In the lean glossary

Free tools

Guides

SMED changeover worksheet: common questions

More free templates