What are EMI gaskets?
EMI gaskets protect the internal parts of devices from electromagnetic interference. These gaskets fill gaps between components, allowing for any electromagnetic radiation to be rechanneled. This prevents interference from entering or exiting, while also protecting any surrounding electronic components.
Every electronic device generates a certain amount of radiation, so it is crucial to protect the internal components of a device from external sources and vice versa.
EMI gaskets of all materials are built to protect electronic devices from interference, so it’s crucial to consider the appropriate gasket type for each unique application.
At KRA Fabrication, we’re backed by decades of industry experience to help us guide you toward the most cost-efficient, easily-fabricable product on the market. When the joining of surfaces during the EMI shielding process can, at times, introduce gaps into the shielding coverage, our experts help you choose the best solution for your project.
The newest in technology.
Our metallic-particle-filled gaskets are able to combine the sealing properties needed with the electrical properties of metals, making them a top choice for EMI shielding gaskets. These filled gaskets are able to ensure both effective EMI shielding and electrical conductivity.
Although you’ll find different kinds of gaskets depending on material design and geometry, the essential varieties include metal spring fingers, knitted wire mesh, fabric shielding gaskets (FSG), particle-filled silicone gaskets, and form-in-place (FIP) gaskets.
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Finding the right gasket
Each of these gaskets are comprised of materials with individual benefits and are suitable for a specific application. KRA Fabrication works with you to factor in a number of variables when selecting the right gasket, including:
- Compression forces
- Material compatibility
- Corrosion control
- Compression set
- Shielding performance
- Compression range
- Environmental sealing.
What are the different types of shielding gaskets?
FIP Gasket Materials
Form-in-place (FIP) gaskets are some of our specialties at KRA Fabrication. The form-in-place gasket is an electromagnetic interference shielding solution that can be automatically dispensed with optimal precision and minimal manual labor. In 1997, KRA Fabrication was one of the first to use automated FIP gasketing technology, and our tenured team has mastered the practice ever since.
Originally, FIP gaskets were used for applications that involved inter-compartmental isolation to separate signals from other processing units. That said, they’re still best-suited for small form applications, as their beads can be distributed in smaller sizes than other gasketing solutions (0.018” tall by 0.022” wide).
Since the FIP gasket is automatically applied, a simple CAD model can be programmed into the dispensing system to guide the most precise path in for the gasketing, reducing the need for manual labor and thereby preventing any human error during the dispensing process.
Other valuable benefits of form-in-place gaskets include:
- Spatial efficiency
- Highly compressible gaskets
- Rapid turnover for design changes, prototyping and sampling
- Cost-efficient design and manufacturing
Fabric Over Foam Gaskets
For applications that require a low amount of compression force, fabric-over-foam (FOF) gaskets are an ideal solution. While low force is one of its most valuable features, FOF gaskets also offer high conductivity and shielding attenuation, making it an effective shielding solution for a wide range of frequencies. The gaskets can suit a variety of tolerances depending on the application at hand, but this gasket style is particularly well suited for lighter materials. The FOF gasket is commonly used for electronic enclosure sealing applications.
Fabric-over-foam gaskets are preferable for teams looking to save on cost without sacrificing quality. These gaskets require minimal tooling which prevents the need for excessive start-up costs. The conductive fabric is oxidation-resistant, helping it ensure long-term functionality.
Typical applications for fabric-over-foam gaskets include:
- Between screws and chassis
- On heat sinks
- Panel, cover and door seals
- Grounding tabs
- Vent seals
- Improved ground paths
Fingerstock gaskets are typically used when the gasket is involved in a wiping or swiping motion of its corresponding application, such as in a sliding door.
These gasket styles are known for their low contact resistance between joined surfaces of components. This helps to provide tremendous EMI shielding for several applications, filling gaps of various sizes without compromising the efficacy of the shielding properties.
While finger stock gaskets are typically made of copper material, variations include plated finishes of tin, zinc, nickel and other conductive materials to suit several applications. They may also vary in terms of size, design features and mounting methods.
Common mounting methods for finger stock gaskets include: self adhesive clip on rivet mount slot mount solder in place
Finger stock gaskets do, in fact, suit a wide range of applications, but environmental adversities can cause damage to the gasket and impair performance. They should always be used in applications where they’re protected from external environments that propose a threat to the device, or in more moderate environments altogether.
Knitted Wire Mesh Gaskets
Knitted wire mesh gaskets are some of the most durable gaskets available, serving several types of high intensity applications with ease due to its steel mesh exterior.
These gaskets are most commonly made from stainless steel or tinned copper steel wiring to protect the internal core while also offering flexibility in the realm of application and design.
The wiring may also consist of Morel, a nickel-copper alloy. As the wire mesh is flexible and can be molded around the frame of many different shapes of materials, this gasket style suits applications that are rounded, rectangular, double round and more.
The metallic wire encloses the core, which is typically made of rubber, foam or elastomers. Wire mesh gaskets are used most commonly in magnetic and electrical fields.
EPDM Rubber Gaskets
EPDM (ethylene-propylene-diene-monomer) gaskets are made of a synthetic rubber suitable for a wide range of applications.
Given that these gaskets are rubber-based, they’re an ideal gasketing solution for applications that face environmental climate fluctuations (ie: ozone, climate, sunlight, aging, some types chemical exposure, etc.), such as in the automotive or construction industries. Common conditions that EPDM gaskets fare well under include air, hot water, cold water and steam.
These gaskets are typically used for projects that involve glazing, such as window and door sealing, but their capacities range broadly across several industries.