Key takeaway
Fewer codes, chosen with operators, entered in two taps, reviewed weekly. Everything else is a report nobody reads.
01Why the 80-code list dies
Reason-code lists are usually written in a meeting room. They arrive on the floor with sixty to eighty entries, sorted alphabetically, on a screen the operator has to walk to. Within a month, 70% of stops are coded 'Other' and the Pareto is meaningless.
The failure is not discipline. It is design. A code list is a user interface for someone with gloves on and a machine waiting.
02Two levels, twelve codes
Start with two groups, planned and unplanned, and no more than seven codes in each. The first screen shows the group. The second shows the codes for that group, largest buttons first. Two taps, done. Detail can be added later by a supervisor if it matters.
- Unplanned: breakdown, material wait, operator unavailable, quality hold, tooling failure, utilities, no order
- Planned: changeover, tool change, preventive maintenance, break, cleaning, trial run, meeting
- 'Other' exists but is reviewed weekly and either renamed or removed
03Let the system code what it can
Many stops do not need a human at all. A tool-change stop after exactly 400 parts is a tool change. A stop at 10:00 on a Tuesday for 15 minutes is the break. A stop with a spindle-load alarm in the control is a breakdown until someone says otherwise. Auto-coding these leaves operators to explain only what the machine cannot.
04Review weekly, in front of the machine
Once a week, the supervisor, the engineer and one operator look at the Pareto for the line. Not in a meeting room. The question is always the same: what is the largest bar, and what would make it smaller next week? Codes that never appear get removed. Codes that are always 'Other' get split. After a month the list belongs to the floor.