Machine Downtime Recording: How to Record It So It Actually Falls

How do you record machine downtime?

Write one line for every stop longer than five minutes: date, machine, stop time, restart time, minutes lost, one reason code, the action taken and who attended. Write it when the machine stops and when it restarts, not from memory at the end of the shift.

Ask an owner how many hours his machines lost last month and the answer is usually a guess. Ask why, and the answer is "breakdowns" or "no operator". Sometimes that is true. Often it is not.

You cannot reduce a loss that you cannot see. Downtime recording makes it visible.

Start with the simple sum

Take the time a machine is planned to work in a shift. Remove the breaks (lunch, tea, shift change). What remains is the available time. Every minute of it falls into one of three groups.

• Run time: the machine was making parts.
• Set-up time: the machine was being changed over, including loading and unloading.
• Downtime: the machine should have been running but was not.

Run time + set-up time + downtime must add up to the available time. If they do not, some time is missing from your records.

Keep the three groups apart. If you call everything downtime, you lose the true downtime figure. If you leave set-up out, you cannot see it at all, and you cannot reduce it later.

The log: one stop, one line, one code

The log is a single sheet kept at the machine. The operator fills it. The supervisor checks that every line has a code. A good line looks like this (example only):

The code is the heart of the log. "Machine problem" cannot be fixed. "Tooling, insert chipped, no spare at the machine" can be fixed with a box of spare inserts.

Why codes from the first day

Many plants begin with free writing and plan to add codes later. That does not work. Free writing gives words like "problem", "waiting" and "power". The history you have written cannot be sorted later.

Make a short list of codes, about 20 to 25, grouped under a few heads.

The head tells you who owns the fix. This removes the blame game. The question is no longer "who is at fault?" but "who owns this head?"

Weekly Pareto: find the few big losses

Once a week, add up the minutes by code and arrange them from the biggest to the smallest. This is called a Pareto. In most plants, three or four codes make more than half of the lost time.

Example only: in one week a machine lost 400 minutes in 12 stops. Tooling and set-up made nearly half of it. Breakdowns made about a third.

Do not try to fix everything. Pick the top two or three codes. For each one, write an action, an owner and a date. Review it at the next weekly meeting.

You cannot manage the hours you do not record. Write each stop when it happens, and the plant will tell you where to look.

Common mistakes

• Writing from memory at the end of the shift. Small stops vanish and the wrong loss gets the blame.
• Writing only the "big" stops. Five-minute waits for a crane, gauge or drawing add up to more than the breakdowns, and they are the easiest to remove.
• Mixing set-up and downtime. You lose both figures.
• Blaming the operator. Look at the system first. Was a spare insert available? Was the material at the machine?
• No review. A log nobody reads is just extra paper.

How to start in your plant

1. Ask one question: "How many machines do we have, and how many ran yesterday?" The answer is often a surprise.
2. Pick the machine that limits your output and start the log there.
3. Give it the code list on day one.
4. Let the operator write, and the supervisor check every line.
5. Include machines available, machines run and hours lost in the structured daily meeting.
6. After four weeks, make the first Pareto and choose two actions.

Show the lost hours in money too: hours lost × the hourly cost of the machine. Owners act faster when they see rupees, not minutes.