Automated X-ray inspection (AXI) is more often a part of an effective test strategy for today's PCBAs because of the benefits it provides manufacturers in meeting challenges resulting from: 1. Continued product miniaturization amid increased product functionality 2. Increased time to market and time to volume pressures 3. Growth in outsourcing and contract manufacturing The structural defect coverage provided by AXI is complementary to electrical test; AXI helps to increase overall fault coverage when used in combination with flying probe, in-circuit and functional test methods. Despite the benefits offered by AXI, new users sometimes struggle with its implementation due to a lack of experience and procedures on how to optimize the inspection process to achieve stated performance targets. Common concerns among this user group include high false failure rates and defect escape rates. Because AXI is a relatively new test technology, many users are unaware of best practice use-models and continuous improvement methodologies that can be used to stabilize the inspection process and attain targeted performance goals for both defect detection and false failure rates. This paper will demonstrate procedures, use-models and continuous improvement methodologies that AXI users should consider when establishing norms for their own operational practices. Like any manufacturing process, appropriate procedures and metrics must be put in place to attain performance goals. Once suitable operational procedures are in place, even new manufacturing technologies like AXI will perform within predictable and acceptable performance limits. The recommendations and best practices discussed in this paper arc derived from the practical experiences of the authors in their direct work with AXI processes in volume prc duction environments.
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