What is Andon?
Andon is a visual-signal system used in lean manufacturing that lets any worker instantly flag a problem so the team can respond before it spreads. Using lights, boards, or alerts, it makes abnormalities visible in real time. Originating in the Toyota Production System, Andon is the mechanism that turns “stop and fix” into everyday practice.
Where Andon comes from
Andon is the Japanese word for a paper lantern, chosen because early systems used illuminated signals to show line status at a glance. The concept was formalized within the Toyota Production System as a core enabler of jidoka—building quality into the process and stopping to address defects rather than passing them downstream. On a Toyota line, any operator can pull an Andon cord or press a button to call for help, and if the issue is not resolved within a set time, the line stops. This gives frontline workers real authority to protect quality.
How Andon works
An Andon system connects three things: a way to raise the signal, a way to display it, and a defined response.
- Trigger — an operator pulls a cord, presses a button, or an automated sensor detects an out-of-spec condition.
- Signal — a stack light, overhead display board, or digital alert shows the location and nature of the problem.
- Response — a team leader or support group acknowledges the call and comes to the point of the problem to help resolve it, escalating and stopping the line if needed.
The goal is a fast, transparent loop so small issues are caught at the source instead of becoming defects, rework, or downtime.
Andon light colors and types
Most systems use a stack light or board with a simple color code:
- Green — normal operation, everything running to plan.
- Yellow / amber — a developing problem or a call for help; the line is still moving.
- Red — a stopped line or a critical fault needing immediate attention.
Some plants add blue for a quality concern or white for a scheduled event such as a material change. Andon itself can be a physical cord, a button-and-light setup, or a fully digital dashboard that logs every call for later analysis.
Benefits of Andon
Andon shortens the time between a problem appearing and someone acting on it, which limits how far a defect can travel down the line. It empowers frontline workers, surfaces recurring issues through the data it captures, and reinforces continuous improvement by making problems impossible to ignore. Because it drives fixes at the source, Andon supports higher first-time quality, less rework, and better uptime.
Common pitfalls
Andon fails when raising a signal has no reliable, timely response—workers quickly stop using a cord that no one answers. It also breaks down in a blame culture, where pulling the cord is seen as admitting fault rather than protecting quality. Effective Andon needs clear escalation rules, a trained support team, and leadership that treats every stop as a chance to improve, not to punish.
How VSight helps
An Andon signal is only as useful as the help it summons—and the right expert is not always on the floor. When a call for support is raised, VSight AR remote assistance lets a technician escalate to a remote expert the moment an Andon signal goes up: the expert sees the live camera feed and adds augmented-reality annotations directly onto the equipment to guide the fix. VSight Workflow complements this with digital work instructions, SOPs, and checklists so the response follows a standard, repeatable procedure rather than tribal knowledge. As a connected worker platform that is GDPR, HIPAA, and ISO 27001 certified, VSight helps regulated operations document each intervention and close the loop faster.
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Related terms: lean manufacturing, kaizen, 5S
Frequently asked questions
What does Andon mean in lean manufacturing? Andon is the Japanese word for a paper lantern, and in lean manufacturing it refers to a visual-signal system that alerts operators, supervisors, and support teams the moment a problem appears. Popularized by the Toyota Production System, it makes issues visible in real time so they can be fixed at the source.
What are the typical Andon light colors? Most Andon systems use a stack light or board with three colors. Green signals normal operation, yellow (or amber) signals a developing problem or a call for help, and red signals a stopped line or a critical fault that needs immediate attention. Some setups add blue for a quality issue or white for a scheduled event.
How is Andon related to jidoka? Andon is the practical mechanism behind jidoka, the lean principle of building quality in and stopping to fix problems. Jidoka gives any worker the authority to halt production when a defect appears, and the Andon signal is how that stop is triggered and communicated so help arrives quickly.
How does VSight help when an Andon signal is raised? When an Andon signal calls for support, VSight AR remote assistance lets a technician escalate to a remote expert who views the live camera feed and adds augmented-reality annotations to guide the fix. VSight Workflow provides digital work instructions and checklists so the response follows a standard, repeatable procedure.