Issue link: https://iconnect007.uberflip.com/i/304995
May 2014 • SMT Magazine 19 bor outlier, and solder area pad) are collected during the studies. a. aXI 1 (Laminography) AXI 1 type is the largest number of AXI ma- chines in our worldwide manufacturing sites. From our experience, AXI 1 plays a good role of detecting various solder joint defective types (solder bridge, insufficient, excess …) based on experience during the last 15 years; it does not detect 100% of BGA HIP defects effectively. En- gineers from different sites share their knowl- edge, such as an experience with latest software, and new algorithm's features in order to achieve the best performance by maximizing the ma- chine's capabilities. First, we tested two boards with AXI 1 type at site 1, and then used the same program to test the same boards at sites 2 and 3 with a little bit of fine-tuning (editing of threshold settings). The main thresholds which we focused on are: open outlier for pad slice and open outlier for middle ball slice. As we know, each AXI machine flags a pin as a defect if the measurement falls outside of the algorithm threshold limit. So it is important to know the difference between a good and bad solder joint with various measurements data for each algorithm. It is easy to have optimization threshold setting if the measurement difference has a big gap; otherwise it is challenging to make AXI program detecting defects with low false call rate. The main thresholds of adjustment are: open outlier for pad slice and open outlier for middle ball slice. The threshold setting is < -3 for "open outlier lower sensitivity for pad slice", and > 3 for "open outlier sensitivity for mid- dle ball slice." These should be good threshold numbers for many products (BGA packages). Table 1 lists the pins, which are called defect from site 2 based on their threshold settings: open outlier sensitivity for slice 1 (midball) is 3; open outlier lower sensitivity for slice 2 (pad) is -3. The program detected 17 HIP pins from 45 defects (board # 495); and it had seven pins HEaD-IN-PILLoW X-Ray INSPECTIoN continues feATuRe Figure 1: Samples of 2Dx images of defective pins (board #495).