What is visual control?: Extended Entry

Visual control is a process to help increase efficiency and effectiveness by making things visible. Several companies use visual control to make things easier or more effective by the use of visual signals. Quite often the signals come in the forms of kanban or heijunka boxes or colored clothing (if you are a team). For companies who have tried it, visual control makes things more effective by simply making things visible. It has been proven that when things are visible, they remain in our conscious minds. Visual control effectively communicates the information that is needed for decisions to be made.

More often than not, visual control is used to replace textile or numerical data displays with graphical displays. The graphical displays must be simplistic enough that an employee can glance at a sign and easily understand what is being said. Some companies use boards where tools are kept. Other examples of visual control include LED displays, colored lights or computer displays. These devices are usually called Andon boards. Visual control can be considered anything that is business related that is visual. For example, you can post the latest sales report on your cubicle wall and this is considered visual control.

Common reasons to use visual control include:
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• Provide instruction to employees


• - Provide immediate feedback to consumers


• - Convey information


• - Make the problems, abnormalities, or deviation standards visible to everyone so corrective action will be taken ahead of time.


• - Display the operating or progress status in an easy to see format

Quite often kanban or heijunka cards are used as visual control.

The Kanban System
A kanban system uses visual aids to control the movement of materials between different work stations. The name kanban referred to a Japanese sign shop that used a visual image on a sign to communicate the type of products that were sold. The Toyota Production System implemented kanban into their transport container. It is a card that is attached to the transport and storage containers. The purpose of the kanban card is to identify part number and the container capacity. There is other information on the card as well that provides easy, visual, signals to the employees.

Not all companies use the kanban cards for their pull systems. Many companies simply use labels to identify that a container is empty or use areas in their warehouses or production departments to identify a container is empty and needs replenishment.

The kanban system is called a pull system because kanban is used to pull parts from one production stage and move them to the next stage when needed. In a pull system, the material movement only occurs when the work station needing more materials asks for it.

Here are the Toyota dual-card Kanban rules:
1. No parts will be made unless there is a production kanban to authorize production. If the kanban cards are not at a work center, the process will remain idle and the workers will perform other activities. This is the "pull" process in the kanban method.
2. There is only one kanban per container.
3. The containers with kanban cards will contain the same part with the same quantity.

Management must carefully regard the number of kanban at each stage in the process. They must do this because this number stands apart from work in process inventory at that stage in production. The kanban is attached only to full containers and once all the containers have kanban attached, the production will cease unless it is authorized by management. The dual card kanban system enables for productivity to be improved significantly. A manager can reduce the work in process inventory by removing one kanban from the system. Typically a reduction like this is done until a shortage of materials occurs and this shortage will indicate problems that were previously hidden by inventory. Common problems include accident, machine breakdowns, defective products, and production delays. Once you have detected the problem, you can identify a solution and set in place proper procedures to correct the problem.

There are various types of kanban systems that exist. Some companies use metal plates instead of cards or ping pong balls. General Motors uses kanban signals on the computer. The kanban system remains the same with each company, to tell the using department to inform the producing department how much and what product to produce depending upon the demand at the beginning, which is the sale of a product.

What is Heijunka?
Heijunka is another Japanese term that "refers to a system of production smoothing designed to achieve a more even and consistent flow of work." As you can see Heijunka is designed to level the production volume and to level the production by product type. In order to understand production leveling, we will look at the 2 aspects of Heijunka in more detail.

Starting with production leveling, Toyota's view is that production systems vary in the muri and mura and the capacity of a machine is forced in some time periods. Muri or overburden is considered to be all the unreasonable work that management assigns upon workers and machines due to poor organization. Some examples of muri are carrying heavy weights, dangerous tasks (behavior-based safety issues), and working at a significantly faster than normal pace. Muri defines this work as pushing a person or machine to a pace beyond their normal limits. Muri is associated with the preparation or planning phase of the production process. Mura or inconsistency focuses on the implementation and elimination of fluctuation of scheduling. This usually falls to the operations level to schedule the quality and volume of the production process.

The approach Toyota uses to combat muri and mura is to manufacture at a long-term average demand and carry a level amount of inventory to keep up with a variable demand. This means they will have a stable production process and will reduce the frequency of shipments.

Leveling the production by product type is a little different. Most companies produce a mix of products and the quantities of specific products is uneven. Again, the solution Toyota used was to reduce the time and cost of the production changeovers so that smaller batches of products were produced and the lost production time was minimal. This leveled out the demand for certain components and reduced the total inventory that was not used. Toyota uses a heijunka box to achieve the heijunka style efficiencies; this is basically a visual scheduling board that shows the different demand levels for certain products.

Implementing heijunka helped Toyota reduce vehicle production time and inventory. Toyota is known for creating lean manufacturing or the Toyota Production System, as they call it. Several successful companies have looked to their approach to reduce excess waste at their organization and increase overall productivity.

How to implement Visual Control
Implementing visual control in the workplace not only helps to expose the problems, it helps your company eliminate excess waste, unevenness, and deviations. If you would like to implement visual control in your company's workplace, here are a few steps to help you get started:
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• Organize a program committee.


• - Develop a plan and budget.


• - Collect and develop examples and cases of problems or accidents.


• - Publicly announce the start of the program to your company.


• - Provide training and education to employees.


• - Select a day and have everybody apply visual control in his/her own working area.


• - Evaluate the results of visual control


• - Self-Examination and take corrective actions.

Keep in mind that the main purpose behind visual control of to organize the workplace so that a group of people can work together without problems and a manager can easily notice whether or not things are going well. Here are some things you can use to implement visual control:
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• Designate a location for the visual control item to be placed.


• - Indicate the quantity or the maximum amount of inventory


• - Provide a document form that tells employees the items so they can distinguish them from other items.


• - Use colors to designate areas.


• - Use shapes, symbols, characters, numbers, or graphs to identify products or production areas.


• - Try using lights and sounds to designate the visual control.

If implemented properly, visual control will help to reduce the costs of accidents, or minor defects in your products. The goal you need to keep in mind is that you want to increase the efficiency of your staff while maintaining higher profit margins. Visual control is relatively inexpensive and does not take much time to implement. Whether you decide to use flashing lights, or subtle signs, visual control will help your company. With proper management planning and implementation, visual control can set your company on the fast track to success.