What an Andon system is
Andon is a light board (or digital display) that signals the status of a production line in real time, letting anyone, from a distance, know whether a station is running normally or needs help. It's the visual-management piece that makes Jidoka possible: when an operator pulls the Andon cord, the light changes and, depending on severity, the line stops.
The signaling levels
Green
Normal production, no intervention needed.
Yellow
Attention: a station is struggling and needs support before it becomes a full stop.
Red
Line stopped: a serious defect or abnormality was detected and needs immediate intervention.
A problem you can't see isn't a problem — it's a surprise waiting to happen.
The response protocol
An Andon system only works if there's a clear response protocol: who responds to a yellow signal, within what timeframe, and who has the authority to actually stop the line on red. Without that protocol, Andon just becomes decorative lighting.
About the author
Lean Manufacturing & Behavioral Management Specialist
Over 20 years in the automotive and metalworking industries (GM and Dana), Lean Manufacturing practitioner since 2006. SENAI instructor and mentor in Brazil’s Brasil Mais Produtivo program, delivering consulting, training and audits for 50+ companies, combining quality, productivity and people development.