At NEDC, we sell gaskets, lots of them. I would love nothing better than to sell a fully loaded pure silver gasket. Love it. However, I’ll be honest, I don’t think that’s necessary most times. When customers have all the money in the world to spend, sometimes I wish they wouldn’t spend it on a pure silver gasket. Heres the reasons why:
Classifications of Commercial EMI/RFI Gaskets for EMC Requirements
I consider Commercial EMI Gaskets any gasket that is not part of the MIL-DTL-83528. Some EMI/RFI Requirements for commercial applications are:
Specifications/Requirements for Commercial EMI/RFI Gasketing
Title 47 CFR Part 15- Radio frequency devices, i.e auditory assistance device, CB receivers,
(Class A (business), and B (personal use) digital devices)
Title 47 CFR Part 25- Satellite Communications
Title 47 CFR Part 18- Industrial, medical, and scientific equipment
RTCA-DO-160- EMI Test Standard for Commercial Electronics
IEEE STD-299 Method for Measuring Effectiveness of EMI Shielding Enclosures
These include gaskets such as:
-Nickel Graphite (Ni/C) dispersed in a Silicone rubber matrix
-Nickel Graphite (Ni/C) dispersed in a Fluorosilicone rubber matrix
-Nickel Aluminum (Ni/Al) dispersed in a Fluorosilicone rubber matrix
-Nickel Aluminum (Ni/Al) dispersed in a Silicone rubber matrix
What is the MIL-DTL-83528 specification?
MIL-DTL-83528 is a military specification that lays out different compositions, and performance metrics of EMI/RFI gasketing to be utilized in military applications. These gaskets are verified with a modified version of the MIL-DTL-285 specification.
Reasons to Look At Commercial EMI/RFI Gaskets
Customers tend to believe that EMI/RFI shielding elastomers performance, and cost is directly correlated. With many things that is true, however in the case of EMI/RFI gaskets, many times trying a more economic alternative such as Nickel Graphite can be a good thing to try.
- For example, Nickel Graphite EMI/RFI gaskets are often shown to have better, or similar shielding effectiveness performance to silver aluminum EMI/RFI gaskets.
- Commercial EMI/RFI Gaskets are much less expensive, and have much wider availability than their MIL-DTL-83528 (military counterparts).
- Nickel Graphite, & Nickel Aluminum Gaskets can be modified without changing their military specification for small modifications.