Elasto Proxy fabricates EMI gaskets that provide environmental sealing, thermal insulation, and shielding against electromagnetic interference (EMI), a growing problem in electronics and electrical equipment. The elastomers that we fabricate use silicone or fluorosilicone as the base material and are filled with metal or metal-coated particles that provide electrical conductivity.
The EMI shielding materials that Elasto Proxy sources meet tough specifications and standards. We use water jet cutting to convert sheets or extrusions and can also supply you with compression molded EMI gaskets. The advantages of doing business with us include our support for low-to-medium volumes.
Keep reading to learn more and contact Elasto Proxy for all your industrial rubber products.
What are EMI Gaskets?
EMI gaskets fill the gaps between surfaces such as the lids and panels of metal enclosures. Like other types of environmental gaskets, they also seal-out the external environment. What makes EMI gaskets different is that they also keep out electromagnetic interference, a manmade or naturally occurring phenomenon that disrupt or degrades circuits.
When electronic “noise” reaches an EMI gasket, the unwanted signals are absorbed and the resulting electrical current is sent to ground. Normally, silicones and fluorosilicones are electrically insulating; however, the addition of specialized fillers makes them electrically conductive instead. EMI gaskets that contain conductive fabric for physical reinforcement also provide electrical conductivity.
Silicones and Fluorosilicones
Silicones and fluorosilicones are elastomers that provide high elasticity, high compressibility, strong environmental resistance, and broad temperature resistance. They also maintain their physical properties over time and with changes in temperature. With their fluorine additions, fluorosilicones combine the advantages of silicones with greater fuel and chemical resistance.
It’s important to note that the addition of metal or metal-coated particles to a silicone or fluorosilicone base does not make these elastomers hard and brittle. In fact, electrically conductive silicones and fluorosilicones are available in a range of durometers, including compounds as low as 30 Shore A and as high as 85 Shore A.
Electrically Conductive Fillers
The electrically conductive silicones and fluorosilicones that Elasto Proxy fabricates are available with silver-plated or non-silver particles. There are five choices for filler material.
- Nickel-aluminum
- Nickel-graphite
- Silver-aluminum
- Silver-copper
- Silver-nickel
Each of these fillers offers distinct advantages. For example, nickel-graphite is a cost-effective alternative to silver. Silver nickel is very conductive, and nickel-aluminum is corrosion-resistant.
Types of EMI Gasket Materials
The EMI shielding silicones and fluorosilicones that SSP fabricates can be divided into different types. The table below explains.
Type | Description |
MIL-DTL-83528 QPL Certified | Materials are part of the Qualified Product List (QPL) from the U.S. Defense Logistics Agency (DLA) and meet MIL-DTL-83528, a U.S. military specification for EMI gaskets |
Corrosion Resistant | Nickel-aluminum materials that withstand corrosive environments with heavy salt spray |
Soft (Low Shore A) | Softer EMI elastomers for lower closure forces and better sealing capabilities |
Fuel and Solvent Resistant | EMI fluorosilicones that resist jet fuels, de-icing fluids, solvents, and other harsh chemicals |
Low Outgassing | EMI shielding materials with low levels of silicone outgassing for space, medical, and other environments with vacuum pressure and/or high temperatures |
Most Electrically Conductive | Extremely conductive materials with silver-plated fills |
Flame Retardant | EMI silicones that provide UL 94V0 flame resistance |
Reinforced | Reinforced with electrically conductive fabric that helps to prevent tearing in thinner parts |
Most Cost Effective | Nickel-graphite silicones and flurosilicones that aren’t subject to fluctuating silver prices and support smaller, thinner designs |
Water Jet Cut EMI Gaskets
Water jet cut EMI gaskets are ideal for prototyping and low-to-medium production volumes. There’s no tooling to wait for or pay for, and Elasto Proxy’s water jet equipment makes fine, fast cuts as small as 1/2” x 1/2” (12.7 mm x 12.7 mm) and with holes that have diameters as small as 0.01” (0.254 mm). Water jet cutting also supports parts-nesting for more efficient material usage.
Compression Molded EMI Gaskets
Elasto Proxy can also supply compression molded EMI gaskets for prototypes or in low-to-medium production volumes. For large picture-frame style gaskets, molding can increase material yields, especially for jobs that don’t have smaller parts to nest. Compression molding requires tooling, but the molds are less expensive than with injection molding.
Ask Elasto Proxy for EMI Shielding
Elasto Proxy offers EMI shielding gaskets in lower volumes than die cutters can cost-effectively provide. Many of the materials that we fabricate have been independently tested, and a full Certificate of Analysis (COA) is available for every batch. That’s important for military, aerospace, and other projects where traceability is a concern.
To learn more or request a quote, talk to our team.
