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74 PCB007 MAGAZINE I AUGUST 2018 fy their commitment to their product. Product reliability starts with a good base of material suppliers (Figure 2). Statistical process control is the number one factor that drives quality, which in turn de- rives a reliable product to its customers. Each departmental process should be broken down into specific process defects. Those defects should be noted and documented for every piece that makes its way through the man - ufacturing process, whether it be bare board manufacturing or electronic assembly. A de- fect analysis matrix for all departments should also be reviewed daily, to recognize spikes or leading defect contributors in that department process. Whether a spike or leading defect contributor, they must be analyzed and mea- sures put in place to re- duce the defect which also r equires monitoring by continuous tracking. An actual example taken from PNC Inc. showed that 20% of all defect scrap was being generated from electro- lytic copper plating line due to pitting and mouse bites (Figure 3). With combined technical sup- port from their chemical suppler, along with their inhouse lab and engi- neering staff, it was de- termined that the acid cleaner being used was not cleaning the panels sufficiently prior to the plating process. Contin- uous tracking from Sep- tember of 2017 shows the defect rate from the plating line has been re- duced to less than 3%, with the addition of a new acid cleaner. In-process verifica- tions and testing through the manufacturing process flow is highly rec- ommended to maintain not only product qual- ity, but product reliability. In-process verifica- tions can be broken down into two categories: part verification at each process step and the process step itself. Testing is typically a stand- alone process step. Part verification at each process step can be monitored in various ways, such as a first piece article check, or part AQL checks. For ex- ample, the routing process (of a PCB from a panel) would most likely be an FAI check. The FAI will indicate that the part is dimensionally correct within the stated tolerances. An exam- ple of an AQL may be to dimensionally check the same routed pieces in the final inspection Figure 2: Sample supplier list.

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