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.
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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