Page 416 - Design for Six Sigma for Service (Six SIGMA Operational Methods)

Design and Improvement of Service Processes—Process Management 375

Quick Setup Time Reduction
When one-piece flow and a cellular manufacturing system are used, it is
very important that the setup time needed between producing one type of
product and another type of product be greatly reduced. Otherwise, the pro-
duction system will be overwhelmed by frequent, long changeover times
from one type to the next.

The Toyota production system developed many quick setup time reduction
techniques. However, the key idea is to divide the setup time into two cat-
egories of elements: internal elements and external elements. The internal
elements are the actions needed in the setup where the regular production
has to stop. The external elements are the actions needed in the setup where
the regular production does not have to stop. The key strategy in the quick
setup time reduction technique is to redesign the work elements in setup so
that overwhelming amounts of setup work are done externally, that is,
without production stoppage.

There must be at least a thousand years of history using the quick setup time
reduction technique in the restaurant industry. One of the keys for success
in the restaurant business is to reduce the production lead time, that is, the
time from customer order to serving the food. Nobody wants to wait in a
restaurant for hours without food. The kitchen has to be able to switch over
from one item to another without much delay, and the setup time for
different dishes must be very fast. It is impossible to batch-produce the
same dishes and save those as inventory, so one-piece flow should be strictly
enforced. People in the restaurant kitchen found numerous ways to do the
quick changeover. The main trick is to do a lot of preparations off-line, that
is, when there is no customer order or in parallel with the cooking process.
This is the same idea as that of the Toyota production system.

10.5.4 Future State Value Stream Map

As we discussed in Sec. 10.5.3, lean operation techniques can be used to
generate a new process design in order to reduce the product lead time and
to increase process efficiency. The value stream map for the new design is
called the future state value stream map. Figure 10.25 is the future value
stream map for the production system illustrated by Fig. 10.18.

In this future state value stream map, the batch size for the stamping
operation is reduced from 2 weeks of supply to one shift of supply. The
batch line process of welds and assemblies in the old value stream map is
changed to a U-shaped work cell. Several supermarket shelf symbols in