(This is part of a series of posts examining the 14 principles of The Toyota Way. Today we’re looking at The Toyota Way principle 7 about visual controls.)
We’ve all seen speed limit signs and pay attention to them at our own discretion. But have you seen a design like this?
This speed limit sign features a radar detector and digital readout – it provides feedback to you on how fast you’re actually going but also gives you a basis of comparison to the allowable limit. I’ll bet you’re more likely to align your speed to the posted speed limit when you come across this sign. I certainly do.
That’s what good visual controls do – they provide information to you that either forces you or inclines you to act or react.
Principle #7 from The Toyota Way states:
“Use visual controls so no problems are hidden.”
Visual controls should be designed to quickly communicate information to people, indicating whether a condition is acceptable/not acceptable and, equally as quickly, provide some direction of action on behalf of people.
Visual controls can be charts, graphs, gauges, signs, digital readouts, colors, shapes, numbers, letters, arrows, lines – they don’t need sophisticated implementations.
Tool shadow boards quickly indicate to passers-by what tools are missing or being used and where they should be placed when returned.
Labels and floor lines can indicate where equipment is supposed to be placed. If this trash can was found elsewhere in the plant (for whatever reason), all operators would know exactly where it should go.
These kanban racks have labels on each space that indicate what product should be placed there. When you see some boxes missing it means those materials must be replenished soon.
When these machine photo eyes slide out of adjustment, it is easy to tell because the red and green areas would no longer be in alignment.
Many companies have information boards with specific productivity metrics. This is probably the most common form of visual control in manufacturing settings, but these only work if they are both regularly updated and used for dictating how operators should focus efforts and improvements. Many times these boards don’t get the attention they deserve.
Digital productivity signage/monitors can quickly tell a manufacturing line critical information. In this example, the monitor shares the model number, targeted production, production to plan for that line/shift, how much each line has actually produced, and the difference between planned production and actual production.
And of course we have stoplights. When the green light is on you go. When the red light is lit you stop. Simple to understand, standardized across most of the world, relatively simple to implement.