Andon

Introduction: Andon (Visual Warning System)

Andon is a visual and auditory alert system used in manufacturing to signal problems in production. It is a central part of the Jidoka principle within Lean, which combines automation with human oversight to ensure quality.

Background

The concept of Andon originates from the Toyota Production System. Traditionally, it referred to lantern-like lights on the production floor, but today it includes digital displays, alarms, and dashboards. Its purpose is to provide immediate transparency about process status and quality issues.

Key Elements / Features

• Problem detection: Triggered when a worker spots an issue or when sensors identify irregularities.
• Signal activation: Alerts can include flashing lights, sound alarms, or digital messages.
• Colour coding:
  • Green = normal operations.
  • Amber = warning or minor issue.
  • Red = serious issue requiring immediate intervention.
• Accessibility: Workers can often pull a cord or press a button to activate the system, ensuring empowerment at every level.

Applications / Examples

• Automotive plants: Operators stop the line with an Andon signal to prevent defective parts moving forward.
• Electronics manufacturing: Digital Andon boards highlight assembly errors in real time.
• Service environments: Call centres use digital Andon-style dashboards to flag call queues or system failures.

For example, in a Toyota plant, when an assembly worker detects a defect, pulling the Andon cord triggers a red light and sound. The line may stop, ensuring the issue is fixed before production continues.

Relevance / Impact

Andon fosters a culture of accountability, quick response, and teamwork. It prevents minor issues from escalating, reduces downtime, and improves product quality. As part of Lean manufacturing, it directly supports continuous improvement and customer satisfaction.

See also

• Jidoka
• Toyota Production System (TPS)
• Lean Manufacturing
• Visual Management