Solder-Plating Process Control

The objective of this effort is to develop and implement a scientifically based solderability tester (Sequential Electrochemical Reduction Analysis - SERA) as a process control tool during solder plating of electronic circuit boards. The study is to minimize "weak knee" solderibility problems on the curved radius of plated thru-holes. In addition, the design concept for an automated & ruggedized version of the present SERA tester will be developed. Simpex, with its factory automation expertise, will be integrating and implementing the SERA tester at Cedko Inc.'s printed circuit board manufacturing facility. Understanding the cause of oxidized metallization at "weak knee" locations, SERA test data will be collected at five strategic points in the printed circuit board plating line. Procedures specified in Mil-Std-105/E Level II AQL 1.5 will be used for data collection to ensure the largest sample size with minimum labor expenditure. Data collected at these locations will be analyzed to determine the type and amount of oxidation present. These statistical data or oxidation signatures, will in turn, be used to monitor and control the plating processes. In addition to the data collection and interpretation effort, software algorithms will be developed to interpret SERA readings or oxidation signatures in real-time, such that corrective actions can be recommended immediately by the system controller at each of the process control points. From the lessons learned in implementing the SERA tester, the design concept for an automated SERA test station with ruggedized features will be developed. This effort is anticipated to be completed in 6 months.