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

96 THETOYOTAWAYFIELDBOOK

It is implied in the term “single-piece flow” that only one piece will

be between operations. THIS IS NOT GOOD ENOUGH! The agree-

ment needs to be distinctandvisibleto everyone.

If it is not distinct and visible, what will happen?

The agreement will not be followed, which is a deviation (creates

variation) from the agreed-upon standard (we see that in establish-

ing pull we begin to create a structure to support the next phase—

standardization).

How do we make it visual so that it is easily controlled?

Defineanddedicatethe space for one piece. The space is outlined with

tape or paint to show that only one piece is permitted, and a sign or

label is added to further clarify this (a taped square on the table is not

completely clear, so a sign is added for clarification of what the square

means), as shown in Figure 5-5.

In addition to the visual markings, the space could be physically limited

(controlled) by allowing only enough room for a single piece. This

technique is especially effective when the parts are oriented vertically

and can be placed into a slot, thus controlling the quantity.

One of the primary benefits of creating flow and establishing defined agree-
ments is that the effect of problems can now be seen easily. In the example
above, if consistent deviation from the agreement occurs and the visual controls
are in place, there is another problem.
When deviation is occurring, this is a clear message of an underlying prob-
lem that needs to be addressed. In this situation managers often state, “They
know what they’re supposed to do, but we can’t get them to do it.” Many
managers make the mistake of blaming the operator for not following the
rules, and in fact the operator is compensating for a problem that needs to be
corrected. Stop, and “stand in the circle” to identify what the operator is com-
pensating for.
There are generally two reasons for this condition. The first thing to evalu-
ate is whether the agreement is visual and easily understood by everyone; the

Operation

A

Operation

B

Operation

C

1 PC 1 PC

Figure 5-5. Single-piece flow with visually defined agreement