Page 137 - How To Implement Lean Manufacturing

116 Cha pte r Se v e n

Jidoka Jidoka is not only the most important strategy to implement, it is also one of the
most difficult. However, it is the one I find most often slighted. The danger is that early
in the implementation, other effects will be much more pronounced in terms of achiev-
ing goals. There is always significantly more quantity control reduction to be made in
reducing the wastes of inventory, batches, and transportation than the waste caused by
defects. Hence, these aspects get more attention, at the expense of the jidoka concept. In
addition, most companies, although not very effectively, have been working on defect
reduction for some time. However, I have yet to see even one company that had a jidoka
concept in place—at this point in the implementation—that even remotely resembled the
TPS model. However, later, this weak jidoka system will undermine literally all other
activities. I cannot stress enough that jidoka must be given top priority, even though the
current gains may not seem to warrant it. Return to Chap. 6 and the section titled, “The
Implementation of Jidoka Is Always a Fundamental Weakness” for further information.

Wastes Reduced
• Transportation is reduced by the reduction of distances traveled by using cells,
for example.
• Waiting is reduced because the production lines, while flowing, have little
downtime.
• Overproduction is dramatically reduced on a local basis since local inventories
and batches do not need premature replenishment.
• Defect reduction is the objective of jidoka.
• Inventory reduction is achieved by several of the techniques, including problem
solving, SMED, and minimum lot sizes, to name just a few.
• Movement is reduced when transportation is reduced and distances are
reduced. In addition, since availability is up, there are fewer instances of
reassignment and wholesale personnel movement.
• Excess processing is reduced as all non-value-added activities are reduced.

Summary of Creating Flow
This strategy is simply removing all inventory possible, moving process steps as close
together as possible, and eliminating non-value-added work—plus, the most important
aspect of implementing jidoka.

Strategy 4: Establish Pull-Demand Systems

Conceptual Discussion
Pull systems have two characteristics. First, they have a fixed inventory, so the cycle
stock, plus the buffer and safety stocks need to be determined. Second, they are acti-
vated when product is removed and this signals the upstream process to produce—no
signal, no production. All kanban systems provide this function. However, for some
simple systems such as pull systems within a close coupled cell, for example, the most
effective pull signal often is the “kanban space.”
With a kanban space, when the customer removes the upstream production, the
customer has “opened” the kanban space—this is the pull signal. Afterward, the
upstream process produces more product, but not before. It is the perfect “take one