Table Of Contents
Key Points
- Electromagnetic interference (EMI) gasketing design is critical in industries where a failed gasket can lead to serious consequences, such as the aerospace, defense, and medical devices industries.
- Key considerations in EMI gasketing design include electromagnetic compatibility (EMC) requirements, environmental factors, and mechanical properties.
- The gasketing material and design should provide a reliable seal, be cost-effective, and be designed for manufacturability.
Electromagnetic interference (EMI) gasketing design can be make-or-break in bringing your life-saving and live-changing device to reality. It can often require several iterations to ensure it checks all the right boxes: price, manufacturability, and effectiveness to name a few.
We want to make the design process as easy as possible for you. That’s why the expert engineering team at Modus Advanced wrote this guide on EMI gasketing design considerations. There are seven key EMI gasketing design considerations that we’ve outlined below.
Ready to get started? Let’s dig in.
If you’re still looking for that perfect partner, you’re in luck! We’ve got the experience and capabilities to get the job right and right on time. Contact us at Modus Advanced today.
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Parker Chomerics EMI Shielding Material Guide: Get it here.
Electromagnetic Compatibility (EMC) Requirements
Electromagnetic shielding is the name of the game – your chosen EMI gasketing material needs to rise to the challenge no matter what is thrown at it. A failed gasket can quite literally mean life or death in the aerospace and defense or medical devices industries. It is critical that the gasketing material and design provide adequate electromagnetic compatibility (EMC) to prevent EMI from escaping the enclosure or entering it.
In the context of gasketing design, EMC requirements refer to the ability of the gasketing material and design to prevent electromagnetic interference (EMI) from leaking out of an electronic enclosure or entering into it.
This can be achieved through the use of conductive gasketing materials, such as metallic gaskets, and/or by incorporating design features, such as overlapping seams, that reduce the likelihood of EMI leaking out of the enclosure. Additionally, the gasketing material and design should be compatible with other components of the electronic system, such as connectors and circuit boards, to ensure a complete and effective EMI solution.
When selecting a gasketing material and design for EMI applications, it is important to consider the specific EMC requirements of the product, including the frequency range and level of EMI shielding required. The gasketing material and design should be tested and validated to ensure that it meets the desired EMC performance specifications, and the results of these tests should be documented for future reference.
Environmental Factors
Up next for consideration is the environment into which the gasket will be placed. Will your gasket be in a dynamic or static environment? Will it be exposed to extreme temperatures? Knowing what kind of seal will be required and what stresses the gasket will be subjected to is incredibly important in the design.Some examples of different types of seals that may be required include:
- Static seals: Static seals are classified as a joining of two surfaces that have no relative motion between each other. Static seals fall into two sub-categories: axial and radial static seals.
- Axial static seals: Axial static seals are created by applying compression forces between the upper and lower surfaces being joined.
- Radial static seals: Radial static seals are created by applying compression forces between the inner and outer surfaces being joined.
- Dynamic seals: Dynamic seals exist when there is motion between the surfaces being sealed. Dynamic seals fall into three sub-categories: reciprocating, rotary, and oscillating seals.
- Reciprocating dynamic seals: Reciprocating dynamic seals are required when there is reciprocating motion along a single axis between inner and outer surfaces.
- Rotary seals: Rotary seals are created when there is rotational motion between the surfaces being sealed.
- Oscillating seals: Oscillating seals are created when a shaft rotates through a specific number of turns around an axis, ultimately causing oscillation.
Finally, consider the industry you are designing your gasket for. Military equipment, for example, is often subjected to harsh environmental conditions, such as high temperatures, high humidity, and exposure to chemicals and dust. Medical devices are wiped with abrasive cleaning chemicals regularly and can quickly destroy an otherwise functional gasket.
The gasketing material and design should be durable enough to withstand these conditions without losing its sealing properties or becoming damaged.
Mechanical Properties
Following closely behind environmental considerations are the mechanical properties of your EMI gasket. The gasketing material and design should have adequate mechanical properties, such as compression set, tensile strength, and tear resistance, to withstand the stress of assembly and normal use.In addition, you should consider if your gasket will need to be reused multiple times, or if it will be clamped into place once and then never moved.
Sealability
The gasketing material and design should provide an effective, reliable, and repeatable seal to prevent EMI from entering or exiting the enclosure.
In the defense and aerospace industries, the failure of electronic equipment due to EMI can have serious consequences – the gasketing material and design must be highly reliable and provide consistent performance over time.
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Cost
Time is money, and you’re not here to waste yours. At Modus, we understand that you need to get your product to market as quickly and cost-effectively as possible, without sacrificing quality.
This is where working with an experienced manufacturing partner like Modus Advanced comes into play. Getting involved early in the design phase of your custom EMI gasket will only benefit you and will help provide a good balance between performance and cost.
Manufacturing Process
One of the most overlooked parts of the custom gasket design process is ensuring that you are designing for manufacturability. It’s not uncommon for a design to look spectacular on paper, but then get the ax once it makes its way to an attentive manufacturing partner.
Quantity also plays a large part in EMI gasket design. If you only need a few, then you are pretty free to design as you’d like. If you know you’ll need your gaskets manufactured in large quantities, you’ll also want to ensure that you are considering how they will be manufactured as you design.
Designing with manufacturability in mind will help you create a custom gasket that not only meets your specifications but can also be manufactured quickly and at the lowest possible cost.
EMI Performance
Your design should be tested and validated to ensure that it meets the desired EMI performance specifications for the specific application. For defense applications, EMI performance may be even more critical due to the potential impact of EMI on the safety of military equipment. With that in mind, it is critical to consider how to be in compliance with military standards such as MIL-STD-461 and MIL-STD-810.
Working with a trusted and experienced EMI gasketing supplier can save you a lot of headaches down the road. The supplier should be able to provide detailed technical information, testing data, and samples to support the selection process.
EMI Gasketing Done Right – the Modus Way
There is a lot to keep in mind when you’re designing an EMI gasket that needs to perform every single time without fail. The considerations we discussed each hold varying weights depending on the application, but at the end of the day, your design needs to hit on three things: price, manufacturability, and effectiveness.
We hope this guide serves as a launching point and helps to give you a sense of direction for your EMI gasketing design project. Don’t spuddle your time away – work with a trusted partner from the start. Contact us today to get started.
