Original Date: 02/19/2007
Revision Date: / /
Best Practice : Micro D FOD Elimination
Raytheon’s Network Centric Manufacturing Center in Largo, Florida, implemented a Foreign Object Debris Elimination process to build cables that contain Micro D connectors. The unique requirements of the customer to X-ray, inspect, and clean the connectors has resulted in a 99.7% acceptance rate.
In September 2005 Raytheon’s Network Centric Systems (NCS) Manufacturing Center in Largo, Florida, began manufacturing Micro D cables for the Missile Defense Agency (MDA). Micro D connectors are used to connect the communications cables in missile guidance systems with pins that are only 0.050 of an inch apart. The connector cannot contain any particles or foreign object debris (FOD) larger than 0.030 of an inch, roughly the thickness of a human hair (Figure 2-3). Because FOD detected in a cable connector renders the cable useless, the MDA required Raytheon Largo to photograph and X-ray every connector at each step of the manufacturing process, which resulted in each cable being photographed and X-rayed more than 150 times before completion of the final product.
Prior to 2005, the Raytheon Largo facility had no process implemented for FOD elimination in its manufacturing environment. Cables were manufactured in an area with overhead lighting, minimal traffic control, benches, and tooling on wheels. Material was stored in the work area in kits until use, and packing material was recycled for future use. The process was a single-station manufacturing process with shared test, inspection, engineering, and material resources. No specialized training was given to any employees, which resulted in a large amount of costly rework on rejected cables.
Raytheon Largo contacted several other companies in the semiconductor industry to gain knowledge in developing a FOD-free environment. Using the knowledge gained from other FOD-elimination experts, Raytheon Largo set up an enclosed Process Cell Isolation manufacturing area with access limited to a small number of vital employees who had taken FOD training. Tooling, shop supplies, chemicals, and cleaning agents were controlled and all personal items were removed to eliminate all possible sources of FOD, tooling. Benches, ovens, microscopes, cameras, chairs, waste baskets, and vacuum cleaners were studied and replaced if found to produce FOD. A material control plan that included component security and tracking throughout the build process was implemented along with a cleaning procedure, with a process control plan developed to assign and control test cables, soldering sequence control, use of connector savers, dedicated test and X-ray machines, audits, and the required use of laboratory coats. The Largo facility also established a partnership with a local company to receive the benefit of an independent and professional high-quality X-ray to ensure Raytheon Largo and its customer an acceptable FOD-free product.
Raytheon Largo’s Micro D FOD Elimination process has resulted in predictable and sustainable throughput, with first-past and test yields exceeding 99% and FOD eliminated in 99.7% of the interconnects manufactured. Cycle time has also been reduced 50%, and there has been a significant reduction in regressive flow. Process controls enacted identify potential issues as they occur. This process has also been recognized as a best practice by the MDA and the Center for Advanced Technologies.
Figure 2-3. Example of FOD
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