Andons and Stack Lights in Lean Manufacturing

In lean manufacturing, there is a term known as an andon, which has been applied to a specific class of control lights, known not only as andon lights but as stack lights and tower lights.

Let’s take a look at the significance of these unique signals that are used to streamline communications and efficiency in lean manufacturing.

What Is Lean Manufacturing?
First, we need to develop a sense of understanding of what lean manufacturing is.

Quite simply, it is a production process predicated on the ideal of maximizing productivity while simultaneously minimizing waste and inefficiency.

There are eight key “wastes” to be minimized: unnecessary transportation, excess inventory, unnecessary motion, idle time, overproduction, overprocessing, manufacturing defects, and inefficient use of human resource skills.

An andon system, utilizing a special type of signal used in lean manufacturing processes, can help eliminate some of these wastes.

What Is an Andon?
Andon comes from a Japanese word for “paper lantern” that can be used as a signal. In lean manufacturing, an andon system is a form of visual management and communication.

An andon system can be used to capture and direct an operator’s, or supervisor’s, attention to identify the status of processes and take immediate actions to rectify perceived problems.

Andon and Tower Lights
A common andon system used in lean manufacturing is the use of tower lights, which are also known as stack lights, or, fittingly, as andon lights.

Tower lights are lights that are typically vertically oriented, color-coded, and placed in high visibility locations on production floors.

They serve as visual and sometimes audible indicators of a machine’s status, enabling an operator to take the immediate requisite action to redress the issue.

The majority of andon, or tower lights, contain anywhere from one to five lights. Most have a red light, which indicates a machine fault, stop, or failure (or an arrested process), as well as a yellow light, which indicates a flaw or condition that will also need immediate attention, and a green light that signals normal machine or process operation.

Other andon light configurations have blue and white lights, which communicate requests for assistance or other situationally-dependent signals, as defined by the operator or user. Some tower lights have all five, and a few even have alarms that can also be used to capture and direct attention.

What Are the Applications of Tower Lights?
Many industries and processes benefit from the implementation of tower lights, and they have many applications, including:

● Industrial manufacturing
● Industrial and process automation
● Productivity monitoring
● Maintenance call station monitoring and signaling
● Coordination with SCADA supervisory control systems
● CNC machining processes
● Communication within studios and dispatch centers

What Are the Advantages of Tower Lights?
The use of tower lights for communication for any of the applications mentioned in the last section has numerous potential advantages, including but not limited to:

● Improved transparency in production
● Reduced downtime
● Improved operator responsibility and responsiveness
● The development of more streamlined, efficient processes and protocols
● And, most importantly, simultaneously improved productivity and diminished waste

LED Tower Lights at Competitive Prices
If your facility is already equipped with andon lights and you are looking for a long-lasting, energy-efficient solution, consider upgrading your process infrastructure to incorporate replacement LED tower lights.

LED tower lights are longer lasting, more energy efficient, and more reliable than all other alternatives, not to mention the fact that LEDs produce less heat and generate the same luminous efficiencies as even the best alternatives, including HID lamps.

To learn more about LED tower lights and process control lighting available from Menics and Qronz, visit

Their online inventory includes a wide range of LED and incandescent tower lights, along with other process control lamps, in addition to solutions for energy-efficient, wide-area illumination. Consult their online catalog or contact them for further assistance at 800-966-2345.

For more information about Hirschmann Connectors and Sealcon Please visit: Major Electronix Corp.

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