Page 185 - Design for Six Sigma for Service (Six SIGMA Operational Methods)

Value Engineering 157

Monitor
Identify performance
discrepancies

Evaluate
design

Figure 7.9 Two Unequally Important Functions in OR Relation

7.2.5 Step-by-Step Procedure to Establish FAST Diagram
Step 1: List all functions by using the function list illustrated by Table 7.6.
Be sure to identify each function by a verb and noun. Identify basic
functions and secondary functions.
Step 2: Prepare a 1" × 2" card for each function. Take a close look at
all functions and try to identify the relationships among all functions.
We can use the following logical questions for this purpose:
How is this function accomplished?
Why is this function performed?
When is this function performed?
Select the function that you think is the basic function, and apply the logic
questions to the right and left of the basic function. To determine the
function to the right ask, How is this function performed? To determine
the function to the left ask, Why is this function performed? Repeat this
process until the lowest-order function is included. The path of functions
thus created is called a primary path. We may get multiple primary paths.
Step 3: When the primary path has been selected and positioned on the
chart, position all secondary functions that did not fit into the primary
path by applying the When question and add them above or below
the primary path depending on whether they are supporting
functions, independent functions, or actions. If the secondary
functions are actually objectives or specifications, put them into the
upper-left corner of the FAST diagram.

Apply
skill

Inform
customer

Reach Influence Demonstrate
agreement customer capabilities
Figure 7.10 AND Relationship on When Direction