Axi inspection study with heavily shielded Press-Fit connectors (Impel)

The demand for increased network bandwidth and advanced technology has led to the development on complex and high performance backplane/mid-plane connector. Impel connector is the name of connector that meets growing demands of next generation telecommunication and data networking requirement. The usage of this type of connector has become more and more important in today networking product and more and more connectors are mounted onto PCBA due to their high performance in signal integrity and density. However, because its construction and density of the connector, performing inspection is one of the most critical area after insertion (press fit) process with current Automated X-ray inspection (AXI). It is become very challenging for getting clear AXI image with such heavily shielded press fit connectors. In this paper, we would like to share our experience with challenging Impel Press-Fit connector. Current PCBA populated with total 16 Impel connectors are go through AXI inspection process, to ensure that all the pins are properly inserted and ensure no bent pin, crushed, broken off and smashed issues enclosed inside the PCB drill hole. We have been working with AXI-A, AXI-B and AXI-C, and looking for inspection solutions since July 2015. AXI-A is normal AXI (Automated X-ray Inspection); whereas AXI-B are equipped with Computer Tomography (CT) capability. AXI-C is AXI without CT capabilities. AXI-B has the capability to detect connector defect with very clear X-ray images, and judgement of the pass/fail are very much on dependent well trained AXI operator. However, AXI-B testing times are longer than AXI-A, especially inspection PC BA with Impel connectors. We overcome all the arises issues and successfully develop a good method on the algorithm and threshold setting at AXI-B - it is discussed in detail in the paper. With the join studied for the past one year between Flex Penang PI team and AXI-B Engineers including R&D support, our result of the collaboration is very impress. Machine defect escapee rate has been tremendously brought down from about 20% to 0% and false call rate DPPM has reduced significantly from >20,000 to <;2000 PPM.