Page 440 - The Toyota Way Fieldbook

412 THE TOYOTA WAY FIELDBOOK

Notice that each of these loops is a complete closed loop of material and infor-
mation flow. Material flows toward the customer and information flows backward
to trigger the next order from the immediate customer. Each loop can be inde-
pendently worked on from a lean perspective, and the supermarkets buffer one
loop from minor disruptions while another is being changed. A set of “kaizen
bursts,” specific point kaizen activities, are needed to stabilize the process.
Kaizen projects are not replaced by the value stream approach. Individual
processes must be stabilized and variation removed through kaizen projects. A
particularly challenging problem of process variation might benefit from a sophis-
ticated Six Sigma project. Nor does it replace the lean tools approach since lean tools
are needed to implement each piece of the future state value stream—cells, kanban,
etc. What it does do is put the use of these tools and process improvements into a
broader perspective—the material and information flow as a system. It also impacts
the sequence in which implementation occurs. There is often a tendency to imple-
ment one tool at a time, for example, to do quick changeover across the plant. In
the value stream approach you work pull loop by pull loop and do whatever is
required to stabilize, create flow, standardize, and incrementally level that particu-
lar loop. In some cases you may have the resources to work on multiple loops in
parallel, and in other cases you may want to work on them sequentially.

Characteristics
“Learning to see” method Project management approach
Select product family Visual management (“glass wall process”)
Current & future state maps
Develop detailed action plan (“loop by loop”)

STRENGTHS TRAPS
• Efforts are well-integrated within a larger • Can be time consuming
view • Fluff—if no follow-up
• Multiple benefits to value stream are • Requires large involvement to be
common effective
• Results typically well-quantified and • Wide variability in execution
tangible • Can be difficult to identify product
• Experience with lean as a system families and value streams in certain
contexts
• Others outside of model line are not
directly involved.

Figure 19-6. Strengths and traps of the value stream model line approach