Traditionally, the Andon systems are used as following:
Green or No Light: Everything is OK, production is running smoothly.
Yellow light: There is a minor interruption/quality issue in the production line.
Red light: There is a major issue in the production line. Urgent assistance is required.
Depending on the production scenario, more colors and audible signals may be implemented to the stack lights/screens for more functionality.
Benefits of the Andon System
Time savings: Minimal downtime due to quick indication of issues.
Cost savings: Especially in companies who adopted the lean production strategy, any downtime is very costly, therefore quick issue indication is critical.
Manpower savings: With many colors, the problems may be categorized by their criticality. So right person of right knowledge(and salary) will respond to the failure.
Data collection: If integrated to a data collecting system, Andon may provide digital data directly to the system, which can give clues about which machines are prone to failure, so attention and resources may be reserved for the troublesome line.