Toyota Way Fieldbook : A Practical Guide for Implementing Toyota's 4Ps

when the output is too high than it is to get more out if it’s too low. When in
doubt, choose a higher demand and a lower takt time.

Importance of Visual Controls

The use of visual controls is the most important step in the process of develop-
ing standardization. Unfortunately, it is also the aspect of a lean process that is
most often belittled. We frequently hear, “They are just doing 5S.” Perhaps this
is due to the examples of visual control most often cited, namely, markings on
the floor to indicate the location of trash containers and other items in the work
area, which are viewed as “silly” and perhaps insulting to the intelligence of
employees. Another example is signs that are used to identify the proper location
of items or the type of material stored in a location. Managers and employees
often respond with, “We all know what belongs there.” However, when asked
to identify specificconditions such as the standard quantity, the minimum or
maximum, or the supplying operation, the response is usually less certain.
Figure 6-10 demonstrates that the primary reason for visual control is to
define the desired “normal” state (standard), and then to quickly recognize any

Unable to

verify

adherence

Not Defined or

Visible

Variation of

Process

Unable to

correct

variation

Desired

Method

Unable to

understand

variation

Not clear and

understandable

The Desired Method is

“in our heads” and

“everyone knows it”

Desired

method not

followed

Figure 6-10. Lack of visual awareness leads to incorrect methods

Chapter 6. Establish Standardized Processes and Procedures 139