Page 96 - Six Sigma for electronics design and manufacturing
P. 96
The Elements of Six Sigma and Their Determination
65
Figure 2.15 Plot of Example 2.4 data set original (top) and transformed by log x on
the bottom.
the results are transformed back to the lognormal original. It is rec-
ommended that this method only be used when there are critical spec-
ifications that have to be set in order to achieve six sigma.
2.4.5 The use of statistical software for
normality analysis
There are many statistical software packages that can perform the
calculation for Section 4 in this chapter. The exercises in this section
were provided to show the calculations behind these software pack-
ages. When selecting a quality software package, it is important to in-
vestigate several and focus on those that offer a broad range of analy-
sis on many of the tools discussed in this book. Many of the leading
journals, such as those from professional societies like the American
Society of Quality Control (ASQC) offer periodic reviews of quality
software in their magazine, Quality Progress.
2.5 Conclusions
It can be seen from this chapter that the power of the process capa-
bility index is the cooperative joining of responsibility for quality im-
provements between manufacturing and design engineers. Design
