Greene Tweed develops low-compression sealing materials for aerospace

Lansdale, Pennsylvania – Greene Tweed has developed a new fluoroelastomer (FKM) that can meet the stringent requirements set by the AMS7410 aerospace material specification (AMS).

The new technical standard addresses the previous shortcomings of elastomers in terms of withstanding compression set at low temperatures.

The specification is designed to ensure the safety and reliability of aircraft systems under extreme conditions, Greene Tweed explained in a recent statement.

To develop the material, the US rubber components manufacturer explored various options with nitrile rubber (NBR), flourosilicone rubber (FVMQ), and fluoroelastomer (FKM).

“Each material has its strengths and weaknesses but meeting the stringent requirements of AMS 7410 is no easy feat,” says Arturo Flores, product manager at Greene Tweed.

According to Flores, NBR is a very common aerospace material with good low temperature capabilities and good abrasion resistance, but a high compression set at temperatures above 121°C.

FVMQ provides better low-temperature performance but is not suitable for dynamic applications and is incompatible with lubricating oil.

Greene Tweed said its engineers developed Fusion 665, a chemical-resistant elastomer that performs well at both low temperatures (-57°C) and high temperatures (232°C).

When tested for 70 hours at 135°C, the material’s compression set was measured at 9%, compared to NBR at 38%, the company also reported.

“It is specifically formulated to meet and exceed the requirements of AMS 7379 and AMS-P-83461, as well as the new AMS 7410,” explained Flores.

The material, he added, has an “extremely low” compression set, broad chemical compatibility, and good abrasion resistance, thus overcoming the limitations of existing solutions.”