Page 264 - Design for Six Sigma for Service (Six SIGMA Operational Methods)

Theory of Inventive Problem Solving (TRIZ) 233

For a toothbrush, its main basic function can be described as
Toothbrush brushes teeth
(Subject) (Verb) (Object)

Functional Analysis Diagram

The functional analysis diagram is a graphic tool used to describe and
analyze functions. The following graph is a typical template for a functional
analysis diagram:

Action
Subject or Object
field

Where the subject is the source of action, the object is the action receiver.
Action is the verb in the functional statement, and it is represented by an
arrow. In a technical system, the action is often accomplished by applying
some kind of field, such as a mechanical, electrical, or chemical field. For
example, the function “brush teeth” can be described by the following
functional analysis diagram:

Brush
Toothbrush Teeth
mech.
In the diagram, Mech. stands for “mechanical field.” Clearly, brushing teeth
is an application of one kind of mechanical field, force.
In the functional analysis diagram, there are four types of actions. They are
represented by four types of arrows as illustrated in Fig. 9.1.

Normal useful action

Insufficient useful action

Excessive useful action

Harmful action

Figure 9.1 Legends for Various Actions in the Functional Analysis Diagram