Bad and good test effectiveness values are the percentage of PCBs that are properly distinguished as bad or good. This measure differs from test coverage, which is determined by the percentage of defe...

Test coverage (also called defect coverage) is a measure of the ability of a tester to detect defects. It is the percentage of those defects that are “covered” by a test，with 100% representing test co...

In the previous section, the in-circuit test was deemed the most important for achieving the six sigma level. As shown in Table 4.8, significant savings in cost could be achieved if this test method c...

Atypical PCB test method comparison is given in Table 4.5. It can be seen that the test time increases with the complexity of the test per- formed. More complicated tests allow for a higher removal of...

Figure 4.5 is an example of the test methodologies available for PCB assemblies. These methodologies can be summarized as follows:1. Visual test and inspection. These tests use trained operators to in...

Ultimately, all defects have to be removed by testing the individual assemblies that make up the product, and then finally testing the product. Test engineers are concerned about the yield of the prod...

Figure 4.4 is an example of a portion of an IC fabrication line. Only a few operations are shown in order to demonstrate the utility of using Cpk-based analysis for the line. This analysis can be used...

As discussed earlier，some industries have adopted a form of six sig- ma that is based on target values of Cpk. Examples are the auto industries with the QS 9000 (Cpk 1.67 for new and 1.33 for old prod...