Page 360 - Design for Six Sigma a Roadmap for Product Development

330 Chapter Nine

It is proposed to form an aluminum core inside the pipe to prevent it from
deforming. When processing is finished, the core is removed by etching with
an alkali reagent.

9.7 Complexity Reduction/Trimming
Trimming (or “pruning” or “part count reduction”) is a set of system-
atic methods that can be used to eliminate redundant functions and
parts, thus streamlining and simplifying the system. Redundant func-
tions are functions that have little or no benefit to customers.
Sometime redundant functions are hidden and we need to look hard to
identify them. To identify redundant function, it is very helpful to draw
a functional analysis diagram for the system and ask the question for
each function in the model, is this function really needed?
Trimming can also be used to identify and eliminate redundant
parts. Based on the fundamental ideas of ideality and the ideal final
result, the best component is no component; the best utilization of
resource is to use no resource. Reduction in redundant parts will
reduce the cost and complexity of the system. Usually, the simpler the
system, the fewer potential problems it will have.

What kind of parts should be trimmed? We should consider trimming
the following kinds of parts:

■ The parts that deliver no useful functions
■ The parts that deliver many harmful function and few useful
functions
■ The parts that deliver functions that offer low value to customers
■ The parts that have low utilization ratio

What kind of parts can be trimmed?
■ The useful action of the part can be performed by another part in the
system
■ The useful action of the part can be performed by simply altering
another part in the system
■ The useful function of the part can be performed by the part that
receives the action (self-service)
■ The useful function of the part can be performed by a cheap substi-
tute or a disposable substitute

Example 9.30. Using Trimming: Bulbless Lamps During the 1970s, the
Soviet Union launched an unmanned lunar probe to the moon’s surface to
transmit TV pictures to the Earth. A projector using a lightbulb was