Also called setup, setup time, change-over
What is a changeover?
The time between the last good part of one job and the first good part of the next.
What else it is called
- Other names
- setup, setup time, change-over
- In French
- changement de série
Related entries
Understanding changeover
The interval between producing a good part of one job and producing a good part of the next. It covers removing the old tooling, fitting the new, adjusting, running trial parts and getting the first acceptable piece.
The definition matters because the easy version excludes the expensive part. If you measure from machine stop to machine start you miss the trial parts and the dialling-in, which in most plants is where the bulk of the time goes.
Its real cost is indirect. Because changeover time produces nothing, a plant with long changeovers runs longer batches to amortize them. Longer batches mean more inventory, longer lead times, and defects discovered after several hundred parts rather than after five. That chain is why changeover reduction appears so often as the first project with a return.
In practice
Time one with a stopwatch from last good part to first good part. In most plants the measured figure is noticeably longer than the figure the scheduling system assumes.
Frequently asked
Is changeover time the same as setup time?
They are used interchangeably in most plants. Where a distinction is drawn, setup refers to the physical work of fitting tooling and changeover refers to the whole interval including adjustment and trial parts. Measure the whole interval either way.