Lean Manufacturing at a glance - Andon Systems

In the following postings, I will explain some basic concepts used in Lean Manufacturing. Most of the terms are taken from Japanese words, due to being first implemented at Toyota Motor Corporation. Toyota's HQ and main manufacturing facilities are located in the cities of Toyota and Nagoya inside the Aichi prefecture in Japan.

The first term we are going to talk about is “Andon” (Japanese 行灯 - あんどん), which literally means “Paper Lantern”.

A typical Japanese Paper Lantern (行灯)

Andon is a visual feedback system for the production floor that can indicate the status of a machine, manufacturing line or process. It is capable of alert when assistance is needed and empowers operators to stop the production process when a failure is detected.

Andon systems can also include an audible alarm to alert supervisors when there is a change in the status. They are an effective way to alert support personnel who must attend to several automated processes at a time or are not always located in close proximity to the work they oversee.

Generally, the system is hardwired to a machine, set to trigger automatically when there is a problem. In some cases, operators can change the system status by pressing a button.

The system typically indicates where the alert was generated, and may also provide a description of the trouble. Modern Andon systems can include text, graphics, or audio elements. Audio alerts may be done with coded tones, music with different tunes corresponding to the various alerts, or pre-recorded verbal messages.

Andon Lamps Color-code.

Green – Normal operations

Yellow – Warning. Help will be necessary for the near future. Set up is required.

Red – Operation stopped. Urgent attention is needed. Machine breakdown.

Some other colors and its meaning are:

White – End of a production run, required quantity has been produced

Blue – Quality call, a defective unit has been detected

An Andon System in operation.

Some benefits of using an Andon system.

• Makes the state and condition of manufacturing processes easily accessible and very clear – to everyone.
• It helps the industry guide, monitor and ensure productivity.
• Guarantees quality because will be very uncommon for defects to move into the next station.
• Increases the sense of the quality of operation personnel for every product coming into their station.