Andon
行灯·andon·"paper lantern, signal light"
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Andon is a visual signaling system that alerts teams to problems, status changes, or requests for assistance in real time.
Definition
Andon is a visual management system that displays real-time status and alerts teams to abnormal conditions. Originating from Toyota, where lights on the assembly line indicate status (green for normal, yellow for caution, red for stopped), andon can be lights, displays, sounds, or digital dashboards. When workers encounter problems—quality issues, shortages, safety concerns—they activate andon to summon help. This makes problems visible immediately, enables rapid response, and prevents defects from moving downstream. Andon embodies the principle that problems should be exposed, not hidden.
Examples
Each assembly station has an andon cord. When operators encounter problems—missing parts, quality issues, unclear instructions—they pull the cord. The andon light activates, music plays to identify the location, and a team leader has 60 seconds to respond before the line stops. This system catches problems at the source.
Key Points
- Andon makes problems visible in real time, enabling immediate response
- Activating andon should be expected and supported, not criticized
- Response protocols determine what happens when andon is activated
- Andon data reveals problem patterns and improvement opportunities
Common Misconceptions
Andon is just a signal light. Andon is a system—not just the signal but the response protocols, the culture of stopping for problems, and the management support that makes it work.
Stopping the line for problems reduces output. Short-term interruptions prevent larger problems downstream. The total cost of immediate response is far less than the cost of defects escaping to later processes or customers.