Ci-Dell Brings Legacy Parts Back to Life for Defense Contractor

The U.S. military is implementing next generation missile defense radar to detect stealthier weapon technology. One major defense contractor is installing new over-the-horizon radar arrays equipped with AI and machine learning in an undisclosed location. These arrays are in open field areas and comprised of hundreds of antennae, each mounted on a 17-ft long pole.

While inspecting older radar arrays installed 30 years ago, the contractor’s engineers noticed that the epoxy insulators on the pole bases were in remarkably good condition, so they wanted to replicate the insulators for the new arrays. However, recreating legacy parts can be difficult when materials are no longer available in the marketplace. Ci-Dell stepped in to help research and produce new thermoset radar insulators whose chemistry is just as new as the radar’s AI technology.

Reproducing a recipe with new ingredients

Material specs from the original insulators couldn’t be replicated exactly because the epoxy-based resin went obsolete. Ci-Dell connected with its supplier network to find a replacement material that would meet all the same performance requirements. The arrays will be continually exposed to harsh weather conditions for many years, so part strength is the top priority.  

The Ci-Dell engineering team modeled the part and calculated the amount of material needed to fill the part, which is 6 inches tall and 17 inches in diameter. In total, 36 lbs. of compound would be needed to mold each part.

The contractor requested a high-performance fiberglass reinforced epoxy molding compound designed for structural applications. It required mechanical properties that would retain part strength at elevated temperatures with good chemical resistance and excellent dielectric strength. There were no spare parts available to dissect and put under a mass spectrometer, which would be the easiest way to replicate the material’s properties. 

Initial material investigation revealed these high-performance molding compounds would be logistically difficult because they require deep freeze storage to prevent the embedded initiator from reacting prematurely. After researching the supply base, Ci-Dell found a supplier with an advanced shelf-stable epoxy that didn’t need refrigeration.

Perfecting the molding process

The next step was testing performance specs and moldability. Going beyond just digital analysis, Ci-Dell used a similar shaped existing mold and produced physical sample parts with the sample material. The final mold and tooling were still in production at the time.

Epoxy with such a high percentage of long fiberglass strands is not common in most thermoset parts today and is challenging to mold. The layers of fiberglass are dry, so it’s harder to mix with the resin, trapping air in the mold and creating delamination in the parts. 

Through months of trial and errors, the Ci-Dell team determined a process with a proper load pattern for the fiberglass-impregnated resin that improved mold flow and prevented trapped air. 

The defense industry chooses Ci-Dell

Ci-Dell Plastics is one of a few thermoset molders in the U.S. that is qualified to complete this project because it meets the defense contractor’s requirements for AS 9100D certification and NIST 800-171 cybersecurity compliance. Plus, it has a thermoset press large enough to mold the part: a 500-ton compression press. Combining the talents of every department in the company, Ci-Dell has delivered a new high-strength thermoset insulator that will support defense systems around the world.

Need help replicating a legacy part? Contact Ci-Dell for its engineering support, superior expertise in selecting and securing thermoset molding compounds, and high-quality molding services.