How can the shielding effectiveness of the metal casing of the intelligent controller PAC be guaranteed?

Ensuring the shielding effectiveness of the PAC (Power Acoustics Control Assembly) metal housing requires attention to materials, structure, and connection. The housing material should be highly conductive aluminum alloy or steel plate with a thickness of at least 1mm. Structurally, openings and gaps should be minimized. EMI conductive pads (such as beryllium copper springs) should be used at the joint surfaces to ensure continuous contact, with a pad compression of 30%-70%. All openings (such as ventilation holes) should use waveguide plates (aperture less than λ/20, less than 15mm at 1GHz).

All parts of the housing should be secured with screws, with a screw spacing less than λ/20, and star washers should be used to reduce contact resistance. The internal PCB should be grounded to the housing at multiple points via metal supports or conductive foam. Testing should be conducted using a shielding effectiveness tester. After optimization, the housing's shielding effectiveness in the 30MHz-1GHz frequency band should exceed 40dB, meeting the IEC61000-5-7 chassis shielding effectiveness standard.