The two characteristics that the Round Beryllium copper EMI gasket must possess are elasticity and conductivity. The common types of Round Beryllium copper EMI gasket are: Finger-shaped reeds, metal mesh gaskets, conductive rubber, conductive cloth wrapped foamed rubber, spiral tubes, etc. Except for the occasions where there is tangential sliding contact, finger-shaped reeds should be avoided. When there is an environmental sealing requirement, conductive rubber should be used. In other occasions, conductive cloth gaskets can be used. When the frequency of shielding is not high, wire mesh gaskets can also be used. When it can ensure that there is no excessive compression, Spiral tubes can be used. Now let's make a comprehensive comparison of the advantages and disadvantages of these several types!
Metal wire mesh gasket: This is one of the most commonly used electromagnetic sealing materials. Structurally, there are three types: all-metal wire, hollow and rubber core. Commonly used metal wire materials include: Monel alloy, beryllium copper, tin-plated steel wire, etc. Its shielding performance is as follows: the shielding efficiency is relatively high at low frequencies and relatively low at high frequencies. It is generally used in scenarios below 1GHz.
Main advantages/disadvantages: Low price, not easily damaged when over-compressed/relatively low shielding performance at high frequencies.
2. Conductive rubber: It is usually used in situations where environmental sealing is required. Structurally, there are two types: sheet materials and strip materials. Strip materials are further divided into hollow and solid types. The plates come in different thicknesses. The materials are: silicone rubber mixed with copper powder, aluminum powder, silver powder, silver-plated copper powder, silver-plated aluminum powder, silver-plated glass powder, etc. Its shielding performance is as follows: the shielding efficiency is relatively low at low frequencies and relatively high at high frequencies.
Main advantages/disadvantages: It provides both electromagnetic sealing and environmental sealing simultaneously. It is relatively hard and expensive. Due to its soft surface, it sometimes cannot penetrate the oxide layer on the metal surface, resulting in very low shielding efficiency.
3. Finger-shaped reed: It is usually used in situations where the contact surface is in sliding contact. It has a wide variety of properties. The material is beryllium copper, but the surface can be coated in different ways. The shielding performance is high at both high and low frequencies.
Main advantages/disadvantages: Large deformation, high shielding efficiency, allows sliding contact (which is convenient for disassembly)/high price.
4. Spiral tube gasket: A spiral tube rolled from Beryllium copper or stainless steel, with high shielding efficiency (the highest shielding efficiency among all Round Beryllium copper EMI gaskets).
Main advantages/disadvantages: Low price, high shielding efficiency/prone to damage when subjected to excessive compression.
5. Conductive cloth gasket: It is composed of conductive cloth wrapped around a foamed rubber core, usually rectangular in shape, with adhesive backing, and is very convenient to install. The shielding efficiency is relatively high at both high and low frequencies.
Main advantages/disadvantages: Low price, not easily damaged when over-compressed, soft, has a certain environmental sealing effect/Frequent friction will damage the conductive surface layer
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