What Is an Andon Light? Complete Guide

Andon is a Japanese manufacturing term commonly associated with a visual signal or lantern used to communicate status. In lean production, an Andon system makes an abnormal condition visible so the right person can respond quickly. The term does not function as an acronym; it describes the signaling concept used to highlight production conditions, support needs, or process interruptions.

An Andon signal is a visual, audible, or digital alert that communicates a production condition requiring awareness or action. It may show that a machine is operating normally, waiting for material, needs an operator, has a quality hold, or has stopped. Modern systems can also send the signal to dashboards, displays, and support teams so escalation is coordinated in real time.

Andon light meanings are defined by each facility, but green commonly indicates normal operation, yellow commonly indicates a warning or assistance request, and red commonly signals a stop, fault, or urgent issue. Blue or white may identify material, quality, maintenance, or scheduling needs. Clear, documented color standards are essential so every operator and responder interprets the signal consistently.

An Andon system detects or receives a production condition, displays a clear signal, and prompts a defined response. A signal can be triggered manually by an operator or automatically through machine monitoring. Connected systems add context such as downtime reason, job, machine state, and responsible team. This helps maintenance, engineering, quality, or supervision prioritize the issue and resolve it faster.

The purpose of an Andon light is to make production status visible immediately at the machine and across the facility. Rather than allowing a problem to remain hidden until a report or shift review, it alerts the team when support is needed. This supports faster problem solving, reduces idle time, reinforces standard work, and helps leaders focus improvement efforts on recurring losses.

Yes. Connected Andon lights can use direct machine data to represent live conditions such as running, idle, alarmed, in cycle, or stopped. When paired with operator inputs and ERP information, the signal can also identify a likely downtime reason, job context, or workflow need. This avoids reliance on manually set lights that can become inaccurate or outdated during a shift.

Choose colors around a simple response standard that teams can remember and act on reliably. Reserve green for normal status, use yellow for attention or assistance, and use red for stops or urgent abnormalities where appropriate. Define any additional colors narrowly, train every shift, and post the standards near work centers. The response expectation matters as much as the color itself.

A digital Andon solution can work with CNC controls, machine monitoring platforms, ERP systems, RFID identification tools, dashboards, and shop-floor communication software. Harmoni supports major controls including Mazak, Haas, Fanuc, Heidenhain, Siemens, DMG MORI, Makino, and Fadal. It also integrates with manufacturing ERP systems such as Epicor, Infor, JobBoss, ABAS, and ODOO.