Understanding EMI Gaskets & Their Varied Applications

Maintaining effective performance for your electrical device is one of the most important things you need to work on as a manufacturer. For devices that require continuous operation time and again, however, one major challenge that you might need to deal with is electromagnetic interference. 

Fortunately, there have been some innovations in preventing this challenge- particularly, with the EMI gasket. In this article, we’ll look into how the EMI gasket works, as well as what you need to keep in mind when handling the device. 

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What is EMI and Why is it a Concern?

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Electromagnetic interference (EMI) is an issue that just about every device has to deal with. Essentially, it is caused when the electromagnetic radiation from one electrical or electronic device interferes with the seamless operation of another. 

EMI can be a major concern for the proper operation of a device. In general, it affects several aspects of a machine’s operation – including: 

  • Performance Degradation: One of the most significant effects of EMI is the gradual degradation of a device’s performance. For instance, the presence of EMI can cause video or audio distortion, data corruption, and inaccuracies in overall measurement. 
  • Communication Interference: For wireless communication systems, EMI can easily disrupt the movement of signals from one point to another. This cuts the quality of data connectivity and reduces overall flow. 
  • Data Loss and Corruption: EMI can also corrupt the transmission of data, thus leading to loss and errors in aspects such as retrieval and storage. For industries where data accuracy and integrity are paramount, it is impossible to overemphasize the importance of this. 
  • Safety Risks: There are instances where EMI can pose literal safety risks. In medical devices, for instance, EMI can corrupt the accuracy of data readings, meaning that several vital signs required for the efficiency of life-saving equipment won’t be available.  

Understanding EMI Gaskets 

What Are EMI Gaskets

One of the best ways to combat an EMI is with the EMI gasket. Some might know them as EMC gaskets, but they are specialized sealing components that help to prevent radio frequency interference and protect the function of electronics devices and closures.

Generally, EMI gaskets play a critical role in protecting your sensitive electronic equipment, while also ensuring that they work properly. Their focus is on ensuring that all electromagnetic emissions are contained, and that external interference can be as minimal as possible. 

Like every other electronic tool, EMI gasketing  operates by following several characteristics to ensure efficiency overall. Some of these characteristics that make EMI gaskets unique include: 

  • Shielding: The primary goal of EMI gaskets is to conduct electromagnetic shielding. They focus on creating conductive barriers around electronic devices, thus containing and transporting electromagnetic waves.
  • Sealing: An EMI gasket majorly helps to shield against electromagnetic interference. However, the component can also work as a seal to prevent dust and moisture from entering any of your devices electronic enclosures. 
  • Shapes and Profiles: An EMI gasket comes in different profiles and shapes. You can have an EMI gasket strip, an O-ring, or even an EMI gasket sheet. Over the years, we’ve seen an increase in the use of specialized manufacturing processes, which have led to more custom-designed gasket shapes. 
  • Compression: One of the most important parts of creating an EMI shield will be to compress the gasket material between different surfaces. This compression allows you to achieve a continuous conductive path that improves the efficiency of heat movement.
  • Customization: EMI gaskets can also be built to fit custom functions and requirements – from shape and size to material and even the efficiency of shielding. 

In general, an EMI gasket is an important part of electronics devices and equipment that protect against electromagnetic interference and ensure that the products work as they should. The gasket is built to fit each particular device and function, so you want to make sure that you’re aware of what you’re getting. 

Materials Commonly Used In EMI Gaskets 

There are different materials that can be used to make EMI gaskets, to be fair. When selecting a material, you want to make sure that you have an option that can release any excess electrical energy and prevent the buildup of heat. 

So, here are a few of the options available to you:

  • Metal-Filled Elastomers: A metal-filled elastomer is an elastomeric material that has been fitted with several particles of conductive metals. For most manufacturers, you have an option of using graphite, nickel, and some other options. The job of these gaskets is to offer enough electrical conductivity to power the gasket’s work. With a metal-filled elastomer, you get the highest levels of compression set resistance and shielding. They also come in different hardness levels, so feel free to pick which works for you.
  • Conductive Foams: Silicone and polyurethane foam are just two of the options available when you need to make EMI gaskets. They offer impressive compression, making them perfect for creating reliable seals.
  • Metal Foils: You can also consider thin metal foils like copper and aluminum when making an EMI foam. These materials are known to be conductive, and they can also work when you don’t have so much space to work with. 
  • Wire Mesh: These types of gaskets come with fine metal wire mesh enclosed within an elastomeric matric. The mesh is very conductive, and it is also compressible.
  • Conductive Silicone: Silicone has established a reputation as one of the most widely used materials worldwide. Additionally, you can rely on the material to be useful when making shielding gaskets. For even superior sealing abilities, silicone might be used with another conductive substance. Resistance to any environmental elements will be added to this.
  • Nickel-Plated Materials: Fabrics with a nickel coating can be added to other materials, such as nylon and polyester, to make conductive fabrics. You can use these materials a lot because they are recognized to be strong and flexible.

EMI Gaskets’ Working Principle

To provide shielding and guarantee optimum electromagnetic compatibility, we utilize EMI seals. In order to accomplish this effectively, you should adhere to a set of rules and principles. Additionally, EMI gasket manufacturers must adhere to these in order to provide the proper EMI insulation products:

the conductive barrier 

This was also said earlier. For EMI gasket manufacturers, it is important to select the right conductive materials. Remember that the material you choose will have to create a barrier around the electronic enclosures. 

With this build, you get the right level of  EMI insulation and will be able to prevent any form of interference.

Electromagnetic Waves and Fields: 

Every electronic device you see generates fields and waves made of electromagnetic materials. These waves can contain interference, and by definition, they can be affected by external interference as well. 

Reflection and Absorption

When an EMI wave comes in contact with the conductive barrier from the EMI gaskets and seals, you see several mechanisms work:

  • Reflection: A few of the waves are reflected off the gasket’s conductive surface, meaning that they won’t be able to access the enclosure.
  • Absorption: Just as well, the materials can soak in a little of the EMI energy, converting it into heat and spreading it to prevent interference. 

Path of Least Resistance

Every electromagnetic wave follows the path where it encounters the least amount of resistance. With a protective path covering the enclosure, an EMI gasket guides the generated energy along this path, preventing it from interfering with the sensitive components in your device. 

Sealing

As you’d imagine, an EMI gasket can also help to properly seal off spaces, preventing the entry of moisture, dust, and other environmental contaminants. With this sealing function, you can ensure that the enclosure’s integrity is optimized while also providing an effective sealing solution.

Compression

For an EMI mesh gasket to create the right shielding action, its material will have to be compressed between two surfaces. This compression will ensure that the gasket can create a conductive path, while also optimizing shielding performance across the board. 

Frequency-Specific Shielding

Currently, there are different EMI shielding gasket variants available. And, each of them is built to provide a specific use based on different frequency standards. So, you want to choose an EMI gasket material that works for your needed frequency range

If you’re unsure what to do here, then feel free to consult your EMI gasket manufacturer. They will be able to understand your needs and work within those parameters. 

Types of EMI Gaskets

One of the most important things you need to know when selecting an EMI gasket is the right gasket option to select. For you to do that, you want to consider factors such as the application of the gasket, the size and shape of the enclosure, and the shielding effectiveness you want to achieve.  

So, here are some types of EMI gaskets you want to consider:

Gasket Strips or Tapes:

This is probably the most popular EMI gasket type available. It is flexible, with an adhesive backing that is made of an EI shielding material. 

EMI tapes are popular because of their ease of application. They are mostly used for sealing gaps and seams in doors, panels, enclosures, and more. 

O-Ring Gaskets

These are ring-shaped or circular gaskets that are built to fit into channels or grooves in an enclosure’s surfaces. They can be used to create seals around access panels and doors, preventing unwanted material entry. 

Sheet or Roll Gaskets

With an EMI sheet, you have a massive shielding material that you can fit into different enclosure sizes and shapes. They are quite flexible, and they do well to cover large areas easily.

Die-Cut Gaskets

Also known for their accuracy, these gaskets are made with specialized cutting equipment. You can find them in different shapes and sizes, all based on your needs. 

Custom-Designed Gaskets

The name pretty much says it all here. These are gaskets that are built to fit specific shapes of enclosures. They are built to meet your specific needs, ensuring that shielding and sealing are accurate at all times. 

Fingerstock Gaskets

An EMI fingerstock gasket comes with different spring-like metal contacts – or, if you will, fingers – that provide shielding and electrical continuity when compressed between surfaces. They are mostly used in applications where frequent access is measured; including and especially rack-mounted electronics. 

Conductive Foam Gaskets:

Made of elastomeric materials, these conductive gaskets offer both environmental sealing and EMI shielding. This makes them especially perfect if you need shielding from dust, moisture, and more. 

Metal Gaskets and Seal

With their conductive metal build, these seals and gaskets are mostly used in high-pressure and temperature applications, where you need optimal reliability and strength. 

Wire Mesh Gaskets

A wire mesh EMI gasket comes with a fine metal wire mesh that is placed in an elastomeric matrix. These gaskets offer both environmental sealing and EMI shielding as well, with use in applications such as aerospace and military industries.

When making a selection, you want to understand your specific application requirements. This will inform the perfect level of EMI shielding, as well as other environmental factors that could jeopardize the function of your device. Focus on a gasket option that optimizes the integrity of your device, and you should be more than fine.  

EMI Gasket Design and Selection 

The design and selection process for EMI shielding gaskets is a process that should be taken with all seriousness. As we already explained, these gaskets come in different forms, with each being viable for a specific task. 

As part of the  EMI gasket design guide, keep these steps in mind:

Define the Application Requirements

You begin by having a clear view of the application for your EMI shielding gasket and what it will need. Things like the type of electronic equipment, the frequency range you’re dealing with, and the closure materials.

Identify the Gasket Type

With the application requirements now set, go ahead to choose the type of EMI gasket you’re working with. Go through the different types above, as well as where they might be compatible with your needs.

Material Selection

Next, select the right gasket material. For this, you want to examine the shielding performance and environmental conditions. As long as the material matches the application frequency range and is able to withstand any environmental challenges, you should be good to go.

Determine Shielding Effectiveness

One of the most significant metrics you want to keep in mind is the shielding effectiveness of your application. Essentially, this is the level of attenuation required for your gasket to protect the electronics and their sensitive components. 

The metric is measured in decibels, and it easily varies based on regulatory requirements and general applications. 

Assess Compression Requirements

Have a thorough examination of your gasket’s compression needs. Remember that proper compression is needed to ensure a reliable seal. 

Size and Shape

Based on the surface that needs to be covered, determine the appropriate size and shape of your gasket. If you’re dealing with an irregular shape, then you might need to work with a customized gasket option. 

Environmental Considerations

Make accommodations for possible environmental factors that can affect the performance of your gasket. These include moisture, temperature extremes, exposure to ultraviolet light, and much more. For longevity in performance, this is especially important. 

Regulatory Compliance

Your selected EMI gasket needs to be in compliance with regulatory standards. These standards vary based on industries and even geographical locations, and you want to make sure that your gasket is in line with each of them going forward. 

Installation and Compression Testing

Your EMI foam or EMI mesh gasket should be easy to install. Just also well, as examines the ease of conducting compression testing on the gasket to confirm its ability to achieve the needed compression force. 

When looking to achieve a reliable seal, this is a very important step. 

Supplier Selection

We always recommend working with reputable suppliers when it comes to EMI gaskets. This is why we at Legenday are in the perfect position to help you out. 

The Industrial Applications Of EMI Gaskets

EMI gaskets find a broad range of industrial applications. Considering that electronic devices are especially prominent in different industries, you can imagine how functional gaskets themselves are. 

Below are a few industries where these gasket variants are useful for: 

Aerospace and Defense

EMI gaskets find use in aerospace and military applications, where they are used to shield electronic components, communication systems, and others from external interference. Essentially, when it comes to ensuring the reliability of aircraft and defense systems, these gaskets are quite useful. 

Telecommunications

In terms of telecommunications equipment, EMI gaskets are also quite useful. They optimize the functionality of cell towers, networking tools, base stations, and more, preventing any interference that can disrupt signal transmission and reception. 

Medical Devices

Patient monitoring systems, MRI machines, diagnostic tools, and more rely on EMI gaskets to ensure precision in operation – especially when it comes to sensitive medical tools. For patient safety and proper medical data transmission, it is important to ensure proper EMI shielding. 

Automotive Electronics

Modern cars come with electrical components. As such, EMI gasketing helps ensure that these components work as they should. From protecting sensors to infotainment systems and communication modules, EMI gaskets ensure that everything with a car’s electronics can work effectively. 

Industrial Control Systems

Moving on, we see a lot of use for EMI gaskets in industrial control systems and automation equipment. Here, the systems protect against interference that could potentially disrupt overall  manufacturing processes. 

Data Centers

Every data center consists of several electronic equipment. With EMI gaskets, you can prevent signal interference and optimize data integrity in these facilities, ensuring that all networking hardware and servers work as they should. 

Consumer Electronics

From smartphones to home entertainment systems and more, EMI gaskets ensure that the electronics we use on a day to day are able to operate properly while complying with electromagnetic compatibility standards. 

Energy and utilities:

To shield their components from interference, power generation systems and utility tools will also require EMI gaskets. This is especially true for electronics control components and communication tools, which tend to be more exposed. 

Oil and Gas

EMI gaskets are used in the oil and gas sector to help ensure the more effective operation of parts like sensors and control systems. The gaskets make sure that everything works as it should because they make these parts more effective.

Maritime and Shipbuilding

A working navigation system is a requirement for every ship, in addition to other parts. When you consider how harsh the maritime environment may be, it becomes even more crucial. You can avoid general interference from onboard and external sources with EMI gaskets. 

EMI Testing and Compliance 

As an EMI gasket manufacturer, you need to understand the importance of the tools you’re making. Just as well, keeping track of the standards that guide the creation of these products will be more than important for you.

Fortunately, we have several standards that help guide the overall design of EMI gaskets. Some of them include:

MIL-STD-461 (Military Standard)

This is an all-encompassing standard used in the defense and military industries to establish requirements for electromagnetic compatibility and control. It outlines the test methods and limits for EMI emissions, as well as the risk factors for military tools. 

MIL-STD-464

Another military standard, MIL-STD-464 serves as a complement for the first option. It shows the requirements for electromagnetic environmental effects as they concern military tools – from platforms and systems to electromagnetic pulses and more. 

IEC 61000 Series

Developed by the International Electrotechnical Commission, the IEC 61000 series of standards is particularly concerned with testing methods for immunity and emissions. It contains specific standards that optimize immunity testing and which help in evaluating the performance of the gaskets when it comes to shielding.

IEEE 299

The Institute of Electrical and Electronics Engineers uses IEEE 299 to guide measurement for electromagnetic shielding. This standard particularly focuses on the effectiveness of shielding for enclosures, gaskets, and other materials. It also outlines test setups and measurement techniques for examining overall performance in shielding. 

ASTM D4935

From the American Society for Testing and Materials, this compliance standard examines test methods for determining the electrical performance of a conductive gasket. Particularly, it looks into the efficiency of the conductive materials used in making the gaskets, as well as other materials used in EMI shielding. 

ISO 11452

The International Organization for Standardization (ISO) is one of the world’s leading regulatory boards as far as product standards go. And, it has set forth the ISO 11452 standards to guide electromagnetic compatibility testing – especially for vehicles. 

Now, these are just some of the testing standards and examples available. You also need to remember that you only need to be compliant with the regulations that affect your industry. For EMI gasket manufacturers, this will be especially important. 

How EMI Gaskets Are Installed

In general, the process of installing EMI gaskets is pretty straightforward. But, you will find that testing and assurance will be especially important here.

A Step-by-Step Installation Guide 

Tools and Materials Needed

To begin with, be sure to write a checklist of the tools you’d need before getting started. These include:

  • EMI gasket material (e.g., gasket strip, O-ring, sheet, etc.)
  • Adhesive, if necessary 
  • Clean, lint-free cloth
  • Cleaning solvent – alcohol, etc. 
  • Cutting tool – scissors, etc. 
  • Ruler or tape measure
  • Utility knife 
  • Protective gloves

Prepare the Surface

The first step here will be to ensure that the enclosure surfaces are clean and free of any contaminants. You can use your clean cloth and solvent to thoroughly go through the surface once and for all. 

Measure and Cut

If the need arises, measure the dimensions of the area where you want to install the EMI gasket. If it’s a sheet or strip, cut it to the required length with a cutting tool, and ensure that you achieve accuracy here.  

Adhesive Application

If you have a gasket option that comes with adhesive backing, then you’d need to get some adhesive and apply it to the gasket material’s back. For this step, you want to be especially careful to avoid any excess squeeze-out – so, apply the adhesive only to where it is required. 

Positioning the Gasket

Carefully place the gasket along the sealing path on the enclosure. Ensure that it properly aligns with the surfaces, and that there is no disproportionate placement. 

Compression and Contact

For your seal to be effective, you want to compress the material between the surfaces when the enclosure has been closed. See to it that the closure mechanism is tightened to provide the right compression for a secure fit.

Compression Testing

If you;d like, you can test the seating of the gasket with a compression test. This might require a measurement of the compression force or distance, based on the gasket design and use. 

Visual Inspection & Testing

While the compression test is optional, a general test should be done based on the gasket’s application. This allows you to verify that the shielding is effective and that the installation is done right. 

You can begin with a visual inspection that allows you to ascertain the absence of folds, wrinkles, and gaps in the material. From there, conduct additional tests to ensure compliance with relevant standards based on your industry. 

Documentation

Keep a thorough accounting of EMI gasket installation data to help future references and ensure proper compliance. Down the line, you never know how much these records could come in handy.

Maintenance Procedures For Long-Term Efficiency 

In most cases, you’d find that proper installation is just one of the important things you need to maintain when it comes to EMI gaskets. At the end of the day, an EMI shielding gasket will only be functional long term when it is properly maintained. To that end, you want to keep the following in mind: 

Regular Visual Inspection

Conduct regular visual inspections of your gasket to examine signs of damage, wear, and defects. This should be your first point of call. 

Environmental Exposure

You also want to examine the environmental conditions surrounding the gasket. Extreme humidity, temperatures, and UV radiation can easily affect the gasket’s performance over time, so be sure to inspect the one you have for signs of environmental-related degradation. 

Cleanliness

Another easy step is to ensure that the gasket and surfaces remain clean. Clear out any dust or grime and apply a cleaning cloth and solvent to handle this. 

Compression and Tightness

Make sure that the enclosure mechanism is able to offer enough compression to hold the seal on the gasket. Also, take some time to look at the fasteners and ensure that they are tightly secured. 

Gasket Alignment

When you’re done with the entire installation process, also take time to check that the gasket is aligned properly with each of the surfaces. Any form of misalignment can easily cause gaps that will compromise the seal’s efficiency. 

Record Keeping

Whenever you make inspections or maintenance, keep records of them. Document the details of the processes, the issues you discovered, and how you were able to address them. 

These documents will serve as references for future maintenance and development steps, and you should prioritize them as much as possible. 

Replacement

Once you notice that your gasket is starting to wear or get damaged, you should start looking into replacements immediately. In most cases, you’ll find that mere maintenance won’t be enough to fix some of these defects. So, maintain relationships with part suppliers to ensure that you can make changes when needed. 

Remember to also keep records of all replacements as they are done for future reference. 

Consult Manufacturer Recommendations

As usual, keep an eye on the guidelines put forth by the manufacturer for your specific EMI gasket. This way, you can be sure that you’re using the gasket as it should be applied. 

Conclusion 

EMI gaskets are an important part of every electronic device’s operation. With them in the fold, you’re able to guard against unwanted electromagnetic interference and ensure the optimal operation of all components in your device. 

At Legenday, we can help provide the best EMI gaskets available, allowing manufacturers to easily incorporate them in their devices. Reach out to us for additional consultations or product development, and let’s help you out.

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