Andon

Core meaning

Andon is a visual and/or audible signaling system used in manufacturing to indicate the current status of a process, call attention to problems, or request assistance. It typically provides near real-time visibility of production, machine, or quality conditions to operators, team leaders, and support staff.

An andon can be as simple as a stack light on a machine or as complex as a plant-wide digital dashboard integrated with MES or other shop-floor systems.

How andon is used in manufacturing

In industrial and regulated environments, andon systems commonly:

– Indicate machine or line status (for example: running, stopped, changeover, fault, waiting for materials).
– Allow operators to signal a problem (for example: quality concern, safety issue, equipment malfunction, or missing components).
– Escalate issues when they are not addressed within defined time thresholds (for example: automatic alerts to supervisors or support teams).
– Provide a visible record of events to support root cause analysis and continuous improvement.

Physical implementations include:

– Lights (for example: stack lights with green/amber/red states).
– Display boards or monitors showing line status and counts.
– Audible alarms or buzzers.

Digital implementations include:

– MES or SCADA screens with color-coded status indicators.
– Large-format dashboards in production areas.
– Mobile or desktop notifications linked to plant-floor events.

Relationship to lean manufacturing

In lean manufacturing, andon is associated with:

– Making problems visible immediately at the point of occurrence.
– Enabling rapid response and containment of issues.
– Supporting practices such as line stops, standardized work, and root cause problem solving.

Andon is often mentioned together with concepts like jidoka (automation with a human-empowered stop) and continuous improvement, but it remains a distinct term referring specifically to the signaling mechanism and its use.

Boundaries and exclusions

Andon commonly refers to:

– The signaling mechanism (lights, displays, alerts) and its operating logic.
– The practice of operators or systems triggering a visible signal when conditions deviate from normal.

It does not by itself include:

– The full problem-solving methodology used after a signal (for example: formal root cause methods, corrective actions).
– Overall production control systems such as MES or ERP, although it may be integrated with them.
– General performance dashboards that are not designed to signal and respond to specific events on the shop floor.

Common confusion and related terms

– **Andon vs. MES alarms:** MES alarms may generate events and notifications, but the term “andon” is usually reserved for highly visible status or help signals linked to front-line operations, often with simple color codes or call buttons.
– **Andon vs. escalation workflows:** Andon often triggers an escalation, but the escalation rules and responsibilities are separate from the andon concept itself.
– **Andon vs. general KPIs:** Andon focuses on immediate status and incident signaling, while KPIs and reports aggregate performance over time.

Use in connected and digital shop floors

In integrated OT/IT environments, andon can be implemented or extended by:

– Linking machine or sensor states from PLCs or SCADA to andon lights or screens.
– Using MES to automatically raise digital andon events for conditions such as quality holds, deviations, or missed production targets.
– Capturing andon activations as structured events for later analysis (for example: by shift, product, or equipment).

In regulated manufacturing, digital andon data may support traceability, deviation recording, and structured problem analysis, without itself constituting a validated quality or batch record unless explicitly designed and controlled as such.