Boyd’s engineers began by evaluating different possible materials in tandem with the customer. Initial trials began with a silicone-based foam. While this easily met the necessary V0 flame rating, the large part size caused the foam to be quite expensive to convert based on raw material costs. In addition, due to the silicone construction, expensive custom adhesives or cumbersome mechanical fasteners would be necessary to affix the component inside the server. The customer also tried Polyester-based foams, which were significantly less expensive, but were unable to meet the necessary flame rating.
The customer also tried fabricating the air blocker out of sheet metal to lower costs and eliminate flammability concerns. This seemed like an effective, inexpensive solution, but they quickly found that the metal could hold static charge, which could lead to shorts within the system and equipment failure.
Boyd’s engineers introduced the customer to SOLIMIDE® foam after further experimentation. SOLIMIDE® is a lightweight, open-celled polyimide foam with unique thermal properties that had been successfully implemented in similar applications in the past. While this easily exceeded the flammability requirements, the customer did have reservations about the ability to cost-effectively convert the material into the necessary design. Boyd’s engineers created prototypes with the SOLIMIDE® foam in the exact required dimensions to help alleviate these concerns.
The SOLIMIDE® prototypes were immediately implemented in the servers and met all of the project requirements. The lightweight construction of SOLIMIDE® also allowed the filler to be adhered with an inexpensive low-surface energy (LSE) adhesive, which saved cost and made the installation process significantly simpler.