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...

DPMO and OMI are good tools to calculate PCB assembly line yield and to compare and benchmark electronic PCB assembly in the supply chain. Issues that arise with the implementation of the DPMO and OMI...

DPMO charts are attribute charts used to monitor the quality of PCB assembly lines. They are best used instead of attribute defect charts such as U or C charts. Each type of PCB can be charted every t...

In the previous example, the yield calculations involved two types opportunities—components and solder joints or terminations. This is similar to the problem presented in Figure 4,1, where the IC wast...

The defect rate for new PCBs is usually calculated based on process observations for existing PCBs. Assuming a PCB with through-hole technology, defects are usually obtained from three sources: incomi...