Conductive Elastomer EMI Gasket Design
What are Conductive Elastomer Gaskets?
Conductive elastomers easily fill gaps between mating surfaces while blocking environmental challenges such as moisture, dust, chemical exposure, temperature, and more. In doing so, EMI is shielded effectively and the shielding itself is protected from outlying factors, strengthening the device performance, quality, and over a lifetime.
What was once a premium technology reserved for aerospace electronics and defense systems is now the favorite choice for many engineers who seek to protect their electronic devices from electromagnetic interference. Conductive elastomer EMI gaskets serve a variety of purposes that a traditional rubber gasket would not be able to fulfill.
It is currently employed in a variety of applications across several industries, including:
- Contract manufacturing
- Telecommunications
- Aerospace
- Industrial equipment
- Automotive
- Medical devices
Complex systems and technology often lead to design challenges, and the conductive elastomer gasket helps to ensure optimal functionality. More specifically, conductive gasket materials need to be vigilantly specified such that each of the materials used are appropriate for the desired physical and shielding characteristics.
Failure to ensure compatibility between materials will cause harm to the gasket’s functionality and thereby, to the application itself and surrounding devices. This is particularly prevalent in applications where the gasket or mating material is exposed to external environmental factors which can lead to corrosion.
Both the substrate and gasket materials need to be considered and treated based on the adversities specific to their application in order to enable a synergistic, fortified system.
Designing Your Conductive Elastomer EMI Gasket
When designing the right conductive elastomer for your project, an array of gasket materials may be appropriate depending on the factors pertaining to your application at hand.
The most critical factors to consider when designing a conductive elastomer gasket are:
- Physical properties of the materials chosen
- Compatibility of the materials chosen
- Level of attenuation (or shielding) needed
- Relevant environmental factors within the application
Many different types of conductive elastomer materials can suffice for any single application. Typically, the price of these materials reflects the level of attenuation they yield and the overall quality of the materials themselves. There are hundreds of materials available and even more designs and filler materials to choose from.
Gaskets come in corrosion and flame-resistant grades and can be customized depending on the performance specifications needed. While conductive elastomer gaskets are typically more expensive than their non-conductive counterparts, they are known for their optimal level of performance, making them a required choice for many applications at hand.
The most important factors to consider when designing a conductive elastomer gasket are determining the binding and filler materials and the right gasket design to bring everything together.
Choosing Binding Materials
When choosing binding materials for conductive elastomer gaskets, the first priority is to understand what level of chemical resistance is required for your specific application.
Conductive silicone may suffice, even in applications with varying degrees of environmental adversity. However, Fluorosilicone or EPDM gaskets may be necessary as applications grow in the stress they will receive and the technicality of the devices involved – especially in military, aerospace or other high-impact settings.
Choosing Filler Materials
Choosing the right filler material for your conductive elastomer gasket depends on the electrical and physical properties necessary to provide the desired level of attenuation as well as the potential for galvanic corrosion.
Most fillers are made of any of the following materials:
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Pure silver
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Silver-plated copper
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Silver-plated aluminum
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Silver-plated nickel
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Silver-plated glass
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Nickel-plated graphite
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Nickel-plated aluminum
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Unplated graphite particles
Each new design should undergo thorough system qualification testing.
Selecting the Gasket Configuration
Choosing your gasket configuration will be one of the easiest decisions to make during your conductive elastomer gasket design process. Gaskets can be designed and molded to a variety of shapes and sizes, and they can also be custom made for unique projects or special circumstances.
Finding the most effective gasket for your specific application may take a combination of expertise and finite element analysis. There are general guidelines that can help to refine your search. Get in touch today to speak with our experts about your next project.
Designing the most effective and efficient conductive elastomer EMI gasket takes a wealth of understanding and experience working with different types of gasket materials. It also requires an intimate familiarity with the application at hand in order to make the correct material selections based on their compatibility and conductive properties.
For more information on KRA Fabrication’s EMI gasketing services, get in touch with our team.