Page 184 - Design for Six Sigma for Service (Six SIGMA Operational Methods)

156 Chapter Seven

Determine Analyze Determine
compliance design criteria
deviations

Review
proposals
Figure 7.7 Two Unequally Important Functions in AND Relation

In both Figs. 7.8 and 7.9, the multiple exit lines represent an OR. In Fig. 7.8,
how do you convert books (to delivery)? By extending bookings or fore-
casting orders, not both. “Extend bookings” and “forecast orders” are
equally important. In Fig. 7.9, how do you identify discrepancies? By mon-
itoring performance or evaluating the design. However, “evaluate design” is
less important than monitor performance.

Symbols Along the When Direction
In the FAST diagram, the When direction is the vertical direction. When
several functions are located along the same vertical line, it means that these
functions will be performed at the same time. In addition, when these
functions are connected by lines, it means that there is an AND relationship
among these functions. Figure 7.10 illustrates such an example.

In Fig. 7.10, when you influence the customer, you inform the customer and
apply skills. If it is necessary to rank the AND functions, those closest to the
primary path should be the most important.

Now that we have discussed symbols and notation used in the FAST
diagram, we are ready to go over the step-by-step procedure to complete the
FAST diagram.

Extend
bookings
Convert
bookings
(to delivery)
Forecast
orders
Figure 7.8 Two Equally Important Functions in OR Relation