A guide to Andon in Lean manufacturing.

Operational excellence isn't just a goal; it's a necessity. Organizations strive to streamline processes, enhance product quality, and eliminate waste, often turning to Lean manufacturing principles. Yet even the most optimized operations face disruptions such as defects, equipment failures, and bottlenecks. The real challenge usually lies in identifying and addressing these issues immediately before they cascade into larger problems, causing costly delays and impacting quality.

This is where the Andon system provides a powerful solution, a cornerstone of Andon in Lean manufacturing. More than just a warning light, Andon is a visual management tool designed for real-time problem detection and response, empowering teams to tackle issues head-on. Let's explore the Andon meaning, its function, the role of Andon boards, and practical Andon examples.

This post will cover:

• What is Andon?
• How Andon is used in Lean manufacturing
• What are the types of Andon?
• How Andon systems work
• Decoding Andon signals and boards
• Andon examples
• Benefits of Andon
• Best practices

An Andon is a system of visual, auditory, or both signals designed to alert operators and team members about issues that could affect a larger production line the moment they occur. Coming from the Japanese word for “light,” the first known use of an Andon was in the Toyota Production System, where operators would warn one another of conditions through a series of lighting signals.

What makes an Andon system distinct is that it empowers individual contributors to indicate issues, even entirely stopping production, to prevent broader performance problems.

Andon is one of many components of Lean manufacturing, a broader production process designed to create efficiencies in task completion. It falls into the category of visual management, with controls used to signal statuses and the need for (or lack of) attention from teams.

Lean manufacturing emphasizes efficiency by eliminating waste, from extra material to excessive motion to time spent waiting. While it may seem counterintuitive to stop a line via an Andon to be more efficient, the goal is to address and resolve issues as they happen, so they don’t affect the rest of production and create even more waste moving forward.

Andon indicators are an investment in eliminating waste across the production line. While a makeshift resolution could restore or maintain an action, it’s only temporary and can result in more damage throughout production. Andon applies permanent solutions to the line to ensure repeat errors do not have a trickle-down effect on the rest of production.

Andon systems range from simple manual setups to sophisticated, integrated digital networks.

Manual

A manual Andon is a physical component on a production line that an operator activates to signal an issue. It often consists of ropes or cords suspended above assembly line stations at set intervals.

Operators can quickly act if they notice a problem by pulling the cord to inform team members of a potential issue. The line is attached to a trigger, illuminating a dedicated light to alert others to stop the production line and prevent further problems. The goal is for everyone affected to review and resolve the issue. Once everything is in working order, the cord can be pulled to resume production.

Automatic

As the name implies, an automatic Andon is triggered by a sensor built into the production line that identifies anomalies and brings them to the team’s attention. Rather than requiring initial human intervention, an automatic Andon is always vigilant and incorporates manpower to resolve issues.

How an automatic Andon indicates an issue varies depending on the production line. Systems can be configured to create physical indicators, such as signaling with lights, or digital messages, including emails or texts to stakeholders and supervisors. By automating the process, production lines can free up technician resources.

Digital/smart

A digital or smart Andon system builds on the capabilities of manual and automatic setups by integrating with Industrial Internet of Things (IIoT), Manufacturing Execution Systems (MES), and Enterprise Resource Planning (ERP) platforms. These systems enable advanced features such as real-time dashboards, data-driven alerts, and mobile notifications.

Operators and managers can view issues, statuses, and trends through interactive displays, making it easier to monitor production health across multiple locations. In some implementations, smart Andon systems also offer predictive capabilities — using historical and real-time data to forecast potential issues before they occur. This level of integration supports faster decision-making, enhanced visibility, and continuous improvement across the production environment.

An Andon system operates through a precise process flow designed for rapid response:

1. Problem detection: An operator spots an issue (defect, shortage, safety hazard) or an automated sensor detects an anomaly.
2. Signal activation: The operator pulls the Andon cord, presses a button, or the automated system triggers the alert.
3. Alert notification: Visual and/or auditory signals activate, indicating the location and nature of the problem. Modern systems might also send digital notifications (SMS, email).
4. Response: Designated personnel (team leader, supervisor, maintenance) immediately go to the workstation. This embodies the Lean principle of "Genchi Genbutsu" (go and see).
5. Stop production (if needed): Depending on the severity of the issue, the line may slow or stop.
6. Problem Solving (Root Cause Analysis): The team collaborates at the source to understand the "why" behind the problem, often using techniques like the 5 Whys. While the context is fresh, this immediate investigation is crucial for effective Root Cause Analysis (RCA).
7. Resume production: Once resolved, the signal is deactivated, and production restarts.
8. Learn and Improve (Kaizen): The incident details are logged, providing valuable data for continuous improvement efforts.

Visual management is key to Andon's success. Standardized signals allow everyone to understand the operational status instantly.

Andon signals and colors

• Lights: Stack lights, or tower lights, are commonly used and rely on a color-coded system to indicate status or issues. While customizable, typical meanings are:

  • Green: Normal operations.
  • Yellow/amber: Assistance needed, warning, minor issue.
  • Red: Production stopped, critical problem.
  • Blue (optional): Planned stop (maintenance, changeover).
  • White (optional): Production run is complete.

• Sounds: Alarms, buzzers, or specific tones can supplement visual alerts.
• Manual triggers: Include the classic Andon cord or push buttons.
• Digital alerts: Modern systems use SMS, email, or dashboard notifications.

Andon boards

Andon boards act as centralized visual control centers, displaying the status across multiple workstations or lines. They provide supervisors and support teams with a holistic view of operations.

• Traditional boards: Often large signboards with a matrix of lights corresponding to specific areas, showing status via color.

• Digital boards/dashboards: Modern screens offer greater information density. These can display real-time Key Performance Indicators (KPIs) like:

  • Line/machine Status
  • Production counts (target vs. actual)
  • Cycle times
  • Downtime duration & reasons
  • Quality metrics (defect rates)
  • Overall equipment effectiveness (OEE)

Digital boards often integrate with factory systems (MES, PLCs, IIoT sensors) for automated, accurate data visualization.

While synonymous with manufacturing, the Andon principle of immediate, visual alerting is highly adaptable.

Manufacturing (Toyota): The classic Andon example. An operator spots a defect, pulls a cord, and a light appears on the overhead Andon board, summoning a team leader. If unresolved quickly, the line stops. Other manufacturers like 3M and Caterpillar use similar button-based systems.

E-commerce/logistics (Amazon): Amazon uses a "Virtual Andon Cord" in customer service. If a customer reports a significant product issue, the representative can trigger an alert, potentially halting shipments of that item until the root cause is fixed.

Healthcare: Andon principles improve patient safety. Examples include lights on Code Blue carts signaling daily checks, alarms on infusion pumps, screen alerts for pharmacists about allergies, and Patient Safety Alert Systems that allow any staff member to report hazards.

IT/software development: Visual indicators (red/green lights) on build servers or CI/CD dashboards act as Andons, signaling build failures that require immediate developer attention.

Andon is an element of production communication designed for manufacturing with clear benefits. Issues are detected and addressed as they occur, which helps to create added efficiencies while applying resources as needed. Here are several other key business benefits of Andon:

• Improved information flow. Andon alerts provide a simple, consistent mechanism for communicating line status on a plant floor. Team members can clearly identify an issue and its severity, coming together quickly and openly to address and resolve problems.
• Fewer recurring issues. Andon requires teams to resolve issues as they arise and focuses on long-term solutions rather than short-term fixes. The result is fewer issues lagging the production line and increased efficiency overall.
• Lower manufacturing costs. Andon helps improve product quality through fewer issues, defects, and damaged products. The process also minimizes disruptions that can be costly when hitting production goals.
• Increased productivity. Andon gives supervisors transparency and the ability to respond quickly to issues. It also improves overall equipment effectiveness (OEE) by addressing problems on demand.
• Reduced downtime. Andon limits the time it takes to get back up and running by spotting smaller issues that can be fixed in real time. This can boost the bottom line and help keep production metrics on track.
• Enhanced flexibility. Andon empowers operators and technicians to act independently when problems occur. This engages teams and increases their responsibility for positive production.

Effective Andon implementation goes beyond technology. It requires cultural change and robust processes.

• Clear scope: Define exactly what problems warrant an alert.
• Standardized response protocols: Document who responds, expected times, and escalation paths. Ensure support teams are integrated and trained.
• Appropriate technology and design: Choose user-friendly components suited to the environment. Involve operators in the design.
• Comprehensive training: Train everyone on system operation, signal meanings, and response roles.
• Integration with problem-solving: Ensure alerts trigger structured RCA (like 5 Whys) at the source.
• Monitor, analyze, improve: Log Andon events and use the data for continuous improvement (Kaizen).

Evaluate tools to incorporate Andon into your production process.

Andon is a critical component of Lean manufacturing that enhances communication among team members and creates more efficient production lines. By addressing minor issues as they come up, manufacturers can reduce product and time waste, helping them achieve their production targets and sales goals.

Reducing waste in production takes more than an Andon. Operators and project managers need tools that can support their evolving processes and create additional efficiencies in their day-to-day operations. One area to investigate is project management software that can improve applied processes by supporting communication, tracking, metrics, and more.

Workfront provides business leaders who use Andon and Lean manufacturing with a platform designed to enhance communication and collaboration at scale. From personalized workflows to automated processes, Workfront can streamline production while creating transparency, so you can focus on people rather than processes.

Watch the overview video to learn more.