An Andon system is a visual and operational mechanism that makes an abnormal condition visible, summons a defined response, and records enough context for learning. The light, board, cord, or digital alert is only the signal. The system succeeds when people can call for help safely, response arrives within the process window, and recurring abnormalities lead to verified countermeasures.
Abnormal conditions made visible at the point of work
Response ownership and timing designed into the signal
Recurring calls converted into a focused improvement backlog
Define the abnormality and expected response
Lean Enterprise Institute defines Andon as visual management that shows operating status and signals abnormalities such as machine downtime, quality problems, tooling faults, delays, or material shortages. Translate that principle into specific conditions for each process.
For every signal, define who owns the first response, the expected arrival time, what can be contained at the station, when the line should stop, and how escalation works. A color without a response standard is decoration.
- Trigger that operators and sensors interpret consistently
- Location, asset, order, product, and time
- First responder and escalation path
- Safe containment and stop authority
- Closure evidence and follow-up owner
Design for psychological and operational safety
People must be able to call for help without being blamed for interrupting production. Leaders should treat a call as protection of the standard, not failure by the caller. If response is slow or punitive, teams learn to work around abnormalities.
Make the interface reachable, legible, keyboard- or glove-compatible where needed, and unambiguous. Avoid dozens of codes during the event. Capture the condition and summon help first; classify and investigate with evidence afterward.
Prevent alarm noise and abandoned calls
Use separate severities for awareness, assistance, and stop conditions. Deduplicate repeated machine events, expire stale signals, and route only to people who can act. Show whether a call is acknowledged, who owns it, and how long it has been open.
Measure response time, containment time, recurrence, unknown reasons, and calls that received no action. A high number of alerts is not proof of control; it may show poor thresholds or an unstable process.
Connect Andon data to downtime and root-cause learning
Preserve the trigger, acknowledgement, arrival, containment, restart, and confirmed-cause timestamps. Link the call to machine states, alarms, order, product, material, and quality evidence. This creates a useful timeline without asking the operator to diagnose under pressure.
Review recurring calls by impact and constraint context. Select patterns for structured root-cause analysis, verify countermeasures, and watch recurrence. Keep the Andon reason and confirmed cause separate.
- Signal
Expose the abnormal condition immediately.
- Acknowledge
Make ownership visible to the caller and team.
- Contain
Protect people, quality, equipment, and flow.
- Restore
Return safely to a known standard.
- Learn
Investigate recurring high-impact patterns and verify action.
Pilot where response can actually be supported
Choose one area with clear standards, available team-leader or support coverage, and recurring abnormalities. Observe the current help process before adding technology. A digital Andon cannot compensate for missing response roles or unclear stop authority.
Run the pilot across all relevant shifts. Adjust triggers and staffing from observed response, then connect selected signals to production analytics. The goal is faster recovery and fewer repeats—not more screens.
Practical checklist
- Define observable abnormal conditions by process.
- Give operators clear help and stop authority.
- Assign response ownership, target time, and escalation.
- Show acknowledgement and elapsed time.
- Keep the live symptom separate from confirmed cause.
- Review recurrence, impact, and unanswered calls.
- Verify that countermeasures reduce future Andon events.
FAQ
Questions before you join
Sources and further reading
Authoritative references used to research and verify this guide.