Downtime is any time the machine should be running (there is an order, the shift is under way) but is not producing. It does not matter whether it is 40 seconds or 4 hours — both are lost time, only one of them gets noticed.
Why the reason matters more than the duration
“The machine was down for 70 minutes” tells you nothing you can fix. “The machine was down for 70 minutes: 45 waiting for material, 25 tool change” immediately says who needs to react — the warehouse and the setter. So the goal is not just to measure downtime but to give every stop a reason, while the operator still remembers what happened.
A list of reason codes
Reasons are grouped, and each group says what kind of loss it is:
- Machine breakdown — broken tool, hydraulics, electrical / sensor → availability loss.
- Setup — tool change, product changeover → availability.
- Material — waiting for material, bad material → availability.
- Personnel — no operator → availability.
- Speed — short stops, reduced speed → performance.
- Quality — inspection, rework → quality.
- Outside OEE — break, meeting, planned maintenance.
A good list is short (15–25 reasons), with clear names in the language of the shop floor and an “Other” that requires a note. If “Other” keeps growing, the list needs to be extended.
Example
Press PR-03 stops at 10:14. The tablet immediately shows a red “Uncoded stop · pick a reason”. The operator taps “Broken tool” — done, two taps. Because it is a breakdown and lasts longer than a minute, the call automatically goes to maintenance (Andon). At 10:31 the machine is running again; the 17-minute stop is recorded with its reason, time and who fixed it.
The uncoded stop
The biggest trap is a stop that nobody coded. If the system lets it disappear, after a month “unknown” is the biggest loss in the factory. So an uncoded stop must stay visible — on the tablet, on the board and with the shift leader — until someone gives it a reason.
Micro-stops
Stops of a few seconds are rarely recorded by a person, yet together they easily add up to half an hour per shift. Only an automatic signal from the machine (a pulse per cycle) catches them, and they show up as a performance loss, not as separate stops.
In MachineTakt
Downtime is opened automatically from the machine’s pulse or status, or manually. The operator picks the reason from the factory’s code list, and uncoded stops do not disappear. All stops are then gathered in the Pareto of losses by machine, shift and period.