A visual management tool that highlights the status of operations in an area at a single glance and that signals whenever an abnormality occurs.

An andon can indicate production status (for example, which machines are operating), an abnormality (for example, machine downtime, a quality problem, tooling faults, operator delays, and materials shortages), and needed actions, such as changeovers. An andon also can be used to display the status of production in terms of the number of units planned versus actual output.

A typical andon, which is the Japanese term for “lamp,” is an overhead signboard with rows of numbers corresponding to work- stations or machines. A number lights when a problem is detected by a machine sensor, which automatically trips the appropriate light, or by an operator who pulls a cord or pushes a button. The illuminated number summons a quick response from the team leader. Colored lighting on top of machines to signal problems (red) or normal operations (green) is another type of andon.