Designing a dependable enclosure seal isn’t just about picking or designing a gasket, it’s about how that gasket behaves under compression, for the planned life of the device (hours, weeks, months, days, years, etc.), within your hardware’s mechanical limits. The latest article from the Enclosure Institute™ highlights four key factors that matter most: gap spacing, compression force deflection (CFD), material compressibility, and gasket width.
Check out the extended blog on the Rogers website, The Mechanics of Enclosure Seal Design: Gap Spacing, CFD, and Compressibility, and the video below.
*Disclaimer: The Enclosure Institute™ is a free educational resource created by Marian, Inc. and Rogers Corporation to help engineers navigate enclosure sealing with expert guidance.
Tools for Finding Ideal Compression
1. Define the Gap
Begin by defining the minimum and maximum gap to be filled, keeping in mind required tolerances, coatings or films, thickness of additional materials, and substrate surface texture, and aim for at least a 30% compression window. Doing all of this helps prevent leaks from under-compression as well as 'bottoming out' from over-compression. For a quick way to determine the right starting thickness and compression characteristics, check out Rogers Corporation’s Gap Filling Tool.
Click here to watch the quick video tutorial on how to use the Gap Filling Tool here.
2. Select Material with the Right CFD
Compression Force Deflection (CFD) is the force (expressed in PSI or kPa) that's required to compress the material, at a specified rate of compression, to a given percentage of its thickness. CFD tell us how much force the gasket pushes back with as it is compressed.
Once you've established your gap, match the CFD (pushback force) value that achieves secure sealing without placing excess stress on latches, thin walls, or hinges. The CFD pressure comparison table shown here illustrates recommended CFD ranges for foams compressed to 25%, supporting material selection based on sealing requirements.
3. Material Compressibility and Seal Performance
This comparison clarifies the balance between softer, highly conformable foams, and firmer options that maintain pushback and resist vibration. It also underscores the critical role of gasket width: at a constant thickness and pressure, narrower profiles are more susceptible to leakage, making width a quiet hero in protecting against real-world sealing challenges.
Another great tool you can find on Roger's website is the CFD Curve Tool. The CFD Curve Tool allows you to create a stress-strain curve that's meaningful to your application.
Click here to watch the quick tutorial video on how to use the CFD Curve Tool.
Key Takeaways
- Use the Gap Filling Tool, CFD Curve Tool, Finite Element Analysis (FEA), or pressure-sensitive film tests to spot low-load zones early
- Pair sound mechanics with materials that maintain pushback over time (low stress relaxation, good compression set) to keep enclosures sealed far beyond day one.
Read the extended blog on Rogers’ website here.
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Coming Up Next in Module 3 of the Enclosure Institute™
- Testing your seals for reliability
- And much more!
Working on an enclosure application and not sure where to start or currently knee-deep in an active project and not sure what's next? Contact us and we'll put you in touch with a Sales Engineer in your area. Our technical teams can walk you through all the important considerations to make sure your application is ready to go to market without issues.
