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

108 THETOYOTAWAYFIELDBOOK

Flow, Pull, and Eliminate Waste

The most common perception of lean is that it is about “just in time”—the right
part, the right amount, the right time, the right place. As we see, there is a lot
more to it. The key to eliminating waste is creating flow, and the principles of
pull require the production in a “just in time” manner.
It is best to think of flow on a continuum, as shown in figure 5-11. Even the
dreaded schedules create some degree of flow. At the other extreme is a one-
piece flow process with no inventory between operations. Between, you can
have a supermarket that is being replenished, you can pull parts in sequence
from one process to the next, or you can flow through a lane with a defined
amount of inventory without breaking the FIFO order. Notice that the famous
kanban system in which a supermarket is replenished is not the preferred
choice, but the next worst choice besides scheduling. Kanban is an admission
that inventory is needed and must be managed. Waste is designed into the sys-
tem. Both sequenced pull and FIFO generally require less inventory than super-
market systems and have better flow.

Physically

link

process

steps with

no

inventory

between

Upstream

process

replenishes

what

downstream

customer

took

away

Defined lane

with defined

standard

WIP

between

unlinked

processes in

FIFO

sequence

Push

or

Scheduled

Supermarket

Pull

(Kanban)

Sequenced

Pull

(broadcast)

FIFO

Sequenced

Flow

Continuous

Flow

(1 pc Flow)

Traditional

Batch & Queue

Ideal State

of Lean

Pull from a

feeder in

sequence

Schedule

each

process and

push to the

next

Figure 5-11. Continuum of flow