SSP makes EMC gaskets for EMI shielding and electromagnetic compatibility. Learn how an EMC gasket is made and used.
Electronic devices are becoming smaller, faster, and more interconnected. As a result, protection against electromagnetic interference (EMI) is becoming increasingly important.
One of the most common and effective solutions for preventing EMI problems is by using EMC gaskets. By promoting electromagnetic compatibility (EMC), these components play a key role in ensuring the reliable operation of electronics devices.
What is an EMC Gasket?
An EMC gasket, or electromagnetic compatibility gasket, is a specialized type of seal designed not only to prevent the ingress of environmental contaminants like dust or moisture but also to block or contain electromagnetic interference. EMC gaskets serve a dual role: they act as both a physical barrier and an electrical conductor.
Unlike traditional gaskets made solely of rubber or foam, EMC gaskets incorporate conductive materials—such as metal-filled elastomers, conductive fabrics, or metal meshes—that provide a low-resistance electrical path. This conductive path helps equalize potential differences between two surfaces (such as a device enclosure and its lid), preventing EMI from leaking out or getting in.
How Do EMC Gaskets Work?
EMC gaskets function by creating a continuous conductive path across seams or gaps in an enclosure. Electronics enclosures, especially those made from metal, can act like Faraday cages—structures that shield their contents from electromagnetic fields. However, even small gaps or seams in an enclosure can allow electromagnetic waves to escape or enter, compromising the shielding effectiveness.
EMC gaskets are placed along these gaps or mating surfaces to ensure electrical continuity. When the enclosure is assembled and the gasket is compressed, the conductive material bridges the gap, completing the conductive path and effectively sealing off the enclosure from unwanted EMI. This ensures that the electronic device inside can operate without being disrupted by external noise, and that its own emissions do not interfere with other nearby devices.
Types of EMC Gaskets
There are many different types of EMC gaskets, each designed for specific applications and performance requirements. Some of the most common types include:
Conductive Elastomer Gaskets
These gaskets are made from elastomeric materials such as silicone or fluorosilicone, which are filled with conductive particles like silver, nickel, copper, or graphite. The result is a flexible, compressible gasket that also conducts electricity. This is the type of EMC gasket that SSP makes.
Fabric Over Foam Gaskets
This type consists of a foam core that is wrapped in a conductive fabric, typically a metal-coated polyester or nylon. These gaskets are lightweight, easy to install, and highly effective for lower-pressure applications.
Metal Fingerstock Gaskets
Made from beryllium copper or stainless steel, these gaskets use a series of springy metal “fingers” that provide excellent conductivity and resilience. Fingerstock gaskets are ideal for doors, access panels, and applications where frequent opening and closing are expected.
Wire Mesh Gaskets
These gaskets incorporate fine metal wire mesh, which is usually embedded in a silicone or neoprene base. Wire mesh gaskets offer excellent shielding effectiveness and are often used in environments requiring both EMI protection and environmental sealing.
EMI Gasket Applications
EMC gaskets are used in these and other applications.
Telecommunications Equipment: Routers, servers, and base stations must meet stringent EMI regulations to avoid disrupting nearby devices and communications systems.
Medical Devices: EMI can interfere with sensitive diagnostic equipment or life-support systems, so medical enclosures often rely on EMC gaskets to maintain safety and compliance.
Aerospace and Defense: In military and aerospace applications, the consequences of EMI can be mission-critical. EMC gaskets help ensure the reliability and safety of navigation, communication, and weapons systems.
Automotive Electronics: Modern vehicles are packed with electronic control units (ECUs) for everything from engine performance to advanced driver-assistance systems (ADAS). EMC gaskets help ensure these systems operate correctly even in harsh electromagnetic environments.
Consumer Electronics: Laptops, smartphones, and gaming consoles all rely on EMC gaskets to meet FCC and CE emission standards, preventing interference with other household devices.
Design Considerations for EMI Gaskets
Selecting the right EMC gasket for an application involves these factors.
Shielding Effectiveness: This is a measure of how well the gasket blocks or attenuates electromagnetic interference. It is usually expressed in decibels (dB) and varies based on the frequency range and the type of gasket material.
Compression Set: Gaskets must maintain their elasticity and contact pressure over time to ensure long-term reliability. A gasket with a poor compression set may lose its EMI shielding properties as it ages.
Environmental Resistance: In many applications, gaskets are exposed to extreme temperatures, moisture, chemicals, and UV light. Conductive elastomers are often chosen for their durability in harsh environments.
Mechanical Requirements: The gasket must fit securely and tolerate vibrations, mechanical stress, and repeated assembly without degrading.
Cost and Manufacturability: The complexity of the gasket design and the material choice will directly influence manufacturing costs, so the selection must balance performance and budget.
Conductive Elastomeric Gaskets from SSP
SSP makes conductive elastomeric gaskets from the materials we manufacture at our Made in USA manufacturing facility. To learn more, contact us.
