SMD Spring Contacts vs. Conductive Foam and Gaskets: Which EMI Shielding Method Wins on PCBs?

EMI shielding on a PCB usually comes down to one of a few common methods — conductive foam, gaskets, or spring contacts. Each grounds a shielding can or enclosure to the board, but they don't perform equally over the life of a product.

CONDUCTIVE FOAM & GASKETS

• Compressible, forgiving fit. Foam and gaskets accommodate larger tolerance gaps between mating surfaces without precise alignment.
• Degrades over time. Compression set and material fatigue reduce contact pressure — and shielding effectiveness — over repeated thermal cycling or years of service.
• Variable contact resistance. Foam-based conductivity is generally less consistent than a metal spring contact, especially as the material ages.

SMD SPRING CONTACTS

• Consistent contact pressure. A properly designed spring contact maintains its specified force across its full deflection range, cycle after cycle.
• Long-term reliability. Metal spring contacts don't suffer the compression set that degrades foam and gasket performance over time.
• SMT-compatible, repeatable placement. Delivered in tape-and-reel format for automated pick-and-place, ensuring consistent placement across every board — a level of process control foam gaskets applied by hand don't offer.

WHICH ONE SHOULD YOU SPECIFY

For low-cycle, short-service-life applications, foam or gasket solutions may be sufficient and lower cost. For products expected to perform reliably over years of thermal cycling and mechanical stress, spring contacts generally deliver more consistent, longer-lasting shielding performance.

WHY THIS MATTERS

An EMI shielding failure discovered after a product has shipped is far more expensive to fix than specifying the right contact method at the design stage.

Published by the Seyunda Team · 2026