As technology becomes more sophisticated, many production lines are running with fewer and fewer people. Unfortunately, when things go wrong, the process still requires intervention and correction by a person.
In this article, we will discuss what we mean by visual controls, their benefits and best practices, and provide an example where a bigger problem was prevented by the use of visual controls.
Overview: What are visual controls?
Visual controls are a subset of the larger concept of visual management. Visual management is a process by which information is conveyed via visual means rather than aural, written, or any other ways people communicate.
- Visual displays convey information, for example, by means of posters, diagrams, maps, and signs. They share information but do not provide any direction or instruction as to what action should be taken.
- Visual controls also convey information, but they also provide direction as to what action to take based on the nature of the visual signal.
A red traffic light provides the information that you need to stop your car. A solid yellow line in the street provides information and an understood instruction that you do not cross over that line. Your car’s odometer just tells you how far you have traveled, but the gas gauge will tell you to head to the closest gas station if needed.
A simple shadow board for tools is a visual control since it provides the direction that the hammer can only go in the space that conforms to the shape of the hammer — and not that of the screwdriver.
Color-coding is one of the simplest forms of visual control on equipment. A flashing red light indicates something may not be working as desired and that an inspection and intervention may be necessary. A green flashing light conveys that the equipment is working as planned, and the control action is to do nothing.
The difference between visual displays and visual controls is that visual controls are designed to drive a specific behavior or action. There is a hierarchy of different displays and controls, as represented by the graphic below. This hierarchy can range from simple posters to standard work instructions to a full poka-yoke system.
3 benefits of visual controls
To quote an old phrase, “a picture is worth a thousand words.” Likewise, visual controls are worth a thousand written words. Here are some of the benefits of visual controls.
1. Easily and quickly understand information
When looking at an Excel spreadsheet, it is quick and easy to spot an issue if the cell is colored red. Cells colored green can be skipped over.
2. Improve communications
Assuming that everyone knows that a flashing red light means something has gone awry, everyone should understand what has happened as well as the action needed to correct the situation.
3. Keep the flow moving smoothly
An overhead sign saying “Enter Here” and another saying “Exit Here” should be able to drive the desired behavior of people entering and exiting in the proper locations for a queue.
Why are visual controls important to understand?
Visual controls are a major component of an organization’s overall visual management system. They are a cost-effective and simple way to communicate non-conforming situations so action can be taken.
Since visual cues are the easiest to understand, actions can be taken before a situation can become dangerous.
Respond to problems
You want to have a rapid response system to indications of nonconformity and problems in the system. By understanding what and how a visual control system works, you can address a small problem before it becomes a big one. You can distinguish between the need for correction or corrective action.
Distinguish between visual controls and displays
Visual displays convey information that is usually nice to know. Visual controls clearly signal when action needs to be taken. You need to understand the difference.
An industry example of visual controls
A producer of orange juice had a process by which an arm swung out to push underfilled cartons off the production line. The equipment was automatic and the line was not regularly manned by an operator. Underfilled cartons were a result of dispensing nozzles clogging due to the pulp in the juice. Unfortunately, there were no visual signals of when the process was deteriorating until the operator heard the sound of juice cartons hitting the floor once the cart overflowed with discarded product.
The team implemented a visual control on the cart once the number of cartons hit a certain number. The sensor would activate a red strobe light above the cart to alert nearby operators that something was going on. Any operator in the vicinity could halt the line.
A secondary visual control was put on the scales that weighed the cartons indicating whether the fill weight was repeatedly falling below the weight spec. Again, it activated a visual signal, but in this case, there was also an automatic shutdown of the machine to prevent further filling of underweight cartons.
3 best practices when thinking about visual controls
Visual controls are powerful tools for letting you know about nonconforming performance of any process. Here are a few tips on using a visual control system.
1. Use the appropriate visual management tool
Be sure that you know when it is appropriate to just use a visual display and when to use a visual control. The key is whether you are just sharing information or want somebody to react and do something.
2. Get agreement on what a signal means
If you intend to use a visual signal or signage, be sure that everyone has the same definition and knows the required action to be taken in response.
3. Consider any visual impairments when using color coding
A number of people have red/green color blindness. Consider any physical conditions that may hinder the appropriate understanding and response to color coded signals.
Frequently Asked Questions (FAQ) about visual controls
1. What is the difference between a visual display and a visual control?
A visual display is intended to share information. A visual control is designed to drive a specific action or behavior upon being alerted.
2. What are some examples of visual controls?
Some common visual controls include andon lights, strobe lights, instructional signage, and floor markings.
3. How are visual controls different from visual management?
Visual controls, along with visual displays, are subsets of an overall visual management system.
Final thoughts on visual controls
Visual controls are the quickest and easiest way to signal nonconforming conditions in a process. A visual control is intended to direct a person to a specific action. They are different from visual displays, which are intended simply to share information without a hint of the action that is needed.
In certain situations, you can combine a visual control with sound alerts. Both can provide signals and directions so that workers or participants make the appropriate behaviors, actions, and responses.