What Is Andon?
Andon (Japanese for "lantern") is a visual and audible signaling system that allows any operator to call for help immediately when they detect an abnormality. It is the operational mechanism behind jidoka — the principle that defects must never pass to the next process.
At its simplest, andon is a button or cord at each station connected to a light board visible to the entire area. When activated, it signals which station needs help and triggers a rapid response from the team leader. The system ensures that problems are surfaced in real time, not discovered hours or days later.
Signal Levels
| Level | Signal | Meaning | Response |
|---|---|---|---|
| 🟢 Green | Steady green light | Normal operation — no issues | None required |
| 🟡 Yellow | Flashing yellow + chime | Help needed but production continues | Team leader responds before current cycle ends |
| 🔴 Red | Steady red + alarm | Line stopped — cannot continue safely or with quality | Team leader + supervisor respond immediately |
Yellow Is the Most Important Signal
Most people think red (line stop) is the critical signal. But yellow — "I need help before this becomes a stop" — is where the real value lives. Effective yellow response prevents most red stops. Track yellow-to-red conversion rate: if operators go straight to red, it means yellow responses are too slow and people have given up on getting help before it is too late.
Escalation Structure
When a problem is not resolved at one level, it must escalate to the next — automatically, with defined time limits:
| Time | Responder | Action |
|---|---|---|
| 0 – 1 min | Team Leader | Arrive at station. Assess. Fix or call for support. |
| 5 min unresolved | Supervisor | Join the response. Authorize resources. Contain quality risk. |
| 15 min unresolved | Department Manager | Deploy additional resources. Evaluate production impact. |
| 30 min unresolved | Plant Manager | Strategic decisions: run at reduced rate, shift to other line, notify customers. |
These time thresholds connect directly to the tier meeting escalation structure. What cannot be resolved at T1 (team leader) escalates to T2 (supervisor), and so on.
Every time and responder is the page's own Escalation Structure table: team leader at 0 – 1 min, supervisor at 5 min unresolved, department manager at 15, plant manager at 30. The table's verb in row two is "join the response", so the earlier responders stay and the count on station runs 1, 2, 3, 4 rather than being passed along. Management-minutes are that count multiplied by the minutes it is on station: 1 × 5 = 5 by the 5-minute rung; + 2 × 10 = 25 by 15 minutes; + 3 × 15 = 70 by 30 minutes; and 4 more for every further minute, so 110 by 40. The rung-one close is the same arithmetic stopped at the page's own response target — one team leader at the station within the cycle: 1 × 1 = 1 management-minute, drawn to the same scale. That is the 70 : 1 the two marks compare. No cycle time is assumed and no quantity is added that the page does not give.
Implementing Andon
Andon Data: A Goldmine
Every andon activation is a data point. Over time, andon data reveals:
| Analysis | Insight | Action |
|---|---|---|
| Pulls by station | Which stations have the most problems? | Pareto and focus improvement there |
| Pulls by reason code | What types of problems dominate? | RCCA on top categories |
| Pulls by time of day | Problems cluster at shift start, after break, end of shift? | Adjust startup procedures, handoff improvements |
| Response time trends | Is response getting faster or slower? | Team leader workload, staffing adequacy |
| Yellow-to-red ratio | Are yellows being resolved before they become stops? | Response effectiveness metric |
✅ Healthy Andon Culture
- Operators pull without hesitation
- Team leaders respond within 1 cycle time
- Andon data reviewed daily, trended weekly
- "Thank you for pulling" is the standard response
- Top andon reasons drive improvement projects
❌ Broken Andon Culture
- Operators avoid pulling ("I will get in trouble")
- No one responds — lights stay on for hours
- Andon system installed but not connected or monitored
- Data not tracked or analyzed
- "Just keep running" overrides the signal
🎯 Key Takeaway
Andon is the nervous system of your production floor. It makes every problem visible in real time and triggers an immediate response. Install a simple system, define response roles and time targets, train operators to pull without fear, and mine the data for improvement opportunities. The goal is not zero andon pulls — it is fast response to every pull and steady reduction of the root causes that trigger them.
Interactive Demo
Simulate an andon system on a 4-station production line. Trigger alerts and watch response times.
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