{"id":3712,"date":"2026-03-24T14:29:03","date_gmt":"2026-03-24T06:29:03","guid":{"rendered":"https:\/\/www.handashielding.com\/?p=3712"},"modified":"2026-03-24T14:29:52","modified_gmt":"2026-03-24T06:29:52","slug":"how-contact-force-stability-impacts-emi-shielding-effectiveness","status":"publish","type":"post","link":"https:\/\/www.handashielding.com\/ru\/emi-shielding-effectiveness.html","title":{"rendered":"\u041a\u0430\u043a \u0441\u0442\u0430\u0431\u0438\u043b\u044c\u043d\u043e\u0441\u0442\u044c \u0441\u0438\u043b\u044b \u043a\u043e\u043d\u0442\u0430\u043a\u0442\u0430 \u0432\u043b\u0438\u044f\u0435\u0442 \u043d\u0430 \u044d\u0444\u0444\u0435\u043a\u0442\u0438\u0432\u043d\u043e\u0441\u0442\u044c \u044d\u043a\u0440\u0430\u043d\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u044d\u043b\u0435\u043a\u0442\u0440\u043e\u043c\u0430\u0433\u043d\u0438\u0442\u043d\u044b\u0445 \u043f\u043e\u043c\u0435\u0445"},"content":{"rendered":"

In the world of electromagnetic interference (EMI) shielding, the performance of a gasket is often judged by its material conductivity, shielding effectiveness ratings, and environmental durability. Yet there is one critical factor that engineers sometimes overlook\u2014contact force stability<\/strong>.<\/p>\n\n\n\n

A shielding gasket that loses its compressive force over time will inevitably compromise the very protection it was designed to provide. This article explores why contact force stability matters, how it affects shielding performance, and what design considerations ensure long-term reliability.<\/p>\n\n\n\n

Why Contact Force Matters in EMI Shielding<\/h2>\n\n\n\n

\u042d\u043a\u0440\u0430\u043d\u0438\u0440\u0443\u044e\u0449\u0438\u0435 \u043f\u0440\u043e\u043a\u043b\u0430\u0434\u043a\u0438 \u0434\u043b\u044f \u0437\u0430\u0449\u0438\u0442\u044b \u043e\u0442 \u044d\u043b\u0435\u043a\u0442\u0440\u043e\u043c\u0430\u0433\u043d\u0438\u0442\u043d\u044b\u0445 \u043f\u043e\u043c\u0435\u0445<\/a> function by creating a\u00a0continuous conductive path<\/strong>\u00a0between two mating surfaces\u2014typically a enclosure door and its frame, or two housing components. This conductive path completes a\u00a0Faraday cage<\/strong>, preventing electromagnetic waves from entering or escaping the protected space.<\/p>\n\n\n\n

For this conductive path to be effective, the gasket must maintain consistent electrical contact<\/strong> across its entire length. Any gap, gap, or high-resistance point can become an antenna or leakage path, drastically reducing shielding effectiveness.<\/p>\n\n\n\n

\"EMI<\/figure>\n\n\n\n

The Role of Contact Force<\/h3>\n\n\n\n

Contact force is the compressive pressure that the gasket exerts against the mating surfaces. This force serves two essential purposes:<\/p>\n\n\n\n

    \n
  1. Ensures low-resistance contact<\/strong>: Higher force typically reduces contact resistance by increasing the number of contact points and breaking through thin surface oxides.<\/li>\n\n\n\n
  2. Maintains contact over time<\/strong>: Environmental factors such as vibration, thermal cycling, and material creep can cause gaps to form if the gasket lacks sufficient or stable contact force.<\/li>\n<\/ol>\n\n\n\n

    The relationship between contact force and shielding effectiveness is not linear. A gasket with insufficient force will exhibit rapidly declining shielding performance<\/strong> as even minor gaps appear. Conversely, excessive force may damage the gasket, housing, or fasteners, or create assembly challenges.<\/p>\n\n\n\n

    The Physics of Contact Resistance<\/h2>\n\n\n\n

    The fundamental relationship governing EMI shielding effectiveness is \u043a\u043e\u043d\u0442\u0430\u043a\u0442\u043d\u043e\u0435 \u0441\u043e\u043f\u0440\u043e\u0442\u0438\u0432\u043b\u0435\u043d\u0438\u0435<\/strong>. When two conductive surfaces meet, the actual contact occurs only at microscopic asperities\u2014the high points on each surface. The total contact area is a fraction of the apparent area.<\/p>\n\n\n\n

    Contact resistance<\/strong> is determined by three factors:<\/p>\n\n\n\n