Page 125 - Operations Strategy

100 CHAPTER 3 • SubSTiTuTES foR STRATEgy
nor too little), exactly when needed (not too early or too late), exactly where required
(not to the wrong location) and at the lowest possible cost. It results in items flow-
ing rapidly and smoothly through processes, operations and supply networks. It is
best illustrated with an example. Figure 3.4(a) shows a simple three-stage process. The
traditional approach assumes that each stage in a process or supply network will be
‘buffered’ from the next stage downstream. These buffers ‘insulate’ each stage from its
neighbours, making each stage relatively independent so that if one stage stops oper-
ating for some reason, the next stage can continue, at least for a time. The larger the
buffer inventory, the greater the degree of insulation between the stages, but through-
put times will be slow because items will spend time waiting in the inventories. The
main argument against this traditional approach is that when a problem occurs at one
stage it will not immediately be apparent elsewhere in the system, so the responsibil-
ity for solving the problem will be centred largely on the people within that stage. By
contrast, with a pure lean process, as shown in Figure 3.4(b), items will flow from one
to another only when the subsequent stage requests them. This means that problems at
any stage are quickly exposed. The responsibility for solving the problem is now shared
and is more likely to be solved. By preventing items accumulating between stages, the
operation has increased the chances of the intrinsic efficiency of the process being
improved. The lean approach exposes the process (although not suddenly) to prob-
lems, both to make them more evident and to change the motivation towards solving
the problems.

the elements of lean

Return to our simple example illustrated in Figure 3.4(b). Note how the trigger for
any activity is the direct request of the internal customer; this reflects the emphasis
that lean places on meeting the needs of customers exactly. Second, note how, in the

Figure 3.4 (a) Traditional and (b) lean synchronised flow between stages

(a) Traditional approach – bu ers separate stage
Scheduling and movement information from
operation’s planning and control system

Information Bu er Information Information Bu er Information
inventory inventory
Stage A Stage B Stage C
Deliveries Deliveries Deliveries Deliveries

(b) Lean approach – deliveries are made on request
Information Information
(Orders) (Orders)
Stage A Stage B Stage C
Deliveries Deliveries

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