Page 267 - Handbook of Materials Failure Analysis

3 Reliability Quantitative Specifications 263

3 RELIABILITY QUANTITATIVE SPECIFICATIONS
Technology concepts related to product could be explained with common sense,
although some concepts of new technology take time to be understood. Everyone
understands new product design concepts if the related staff explains them in every-
day communication. Fortunately, the technology concepts related to design verifica-
tion is not difficult to grasp because we, as consumers, use product. For example, the
technology concepts to reduce the noise level of a car engine would be difficult to
understand but assessing the performance improvement would be easy since we can
hear it. The concepts of design verification-related specification are less complex
than that of design itself, and should be easily grasped by CEO. If CEO has difficulty
understanding the verification document, there are illogical sections not to be
explained with common sense when the engineers write it. The necessary logic in
the “thick document” is clarified for any layman to be understood and controversial
as seen in Figure 11.4.
Three kinds of simple logic might be addressed in the verification document.
First, the information is divided into two activities: verification-specifications estab-
lishment and related execution. Second, procedures for how to extract anticipated
issues in a new product need to be addressed in the verification specifications, avoid-
ing omissions of necessary specifications and adding some details pertaining to the
product for a complete set of specs. Third, verification specifications should be clas-
sified into categories according to technological fields in order for related specialists
to review their accuracy. Verification specifications might be clearly presented, pro-
viding brief summaries to clarify the entire specification concepts.

Product value = Function of product quality and price

Meaning of
Reliability
basic
quality
Durability Rate-reliability Conformance-quality
Conformance to
Concept Product life Failure rate
specifications
Percent / year Percent
Unit Year
Percent / hour ppm
Weibull Exponential Normal
Probability
distribution distribution distribution
Design change or
Activities Inspection, screening
completion of specification
FIGURE 11.4
Technology concepts related to design verification: Double ambiguity of product quality.