How to enhance the shielding of the PAC plastic housing for intelligent controllers?

The shielding effectiveness of the PAC plastic housing for intelligent controllers can be enhanced by using conductive coatings, metallization, or the addition of metal foil. Conductive coatings, such as sprayed conductive paint (silver, copper, and nickel fillers) or vacuum aluminum plating, have a surface resistance of less than 1 Ω/sq. Metallization methods include electroless nickel plating and electroplating copper plating, with a thickness greater than 2 μm. Metal foil (such as copper or aluminum foil) is attached internally and bonded with conductive adhesive, with an overlap of at least 10 mm at the seams.

All coatings or metal layers must be reliably connected to the housing grounding points, typically through metal springs or conductive foam to connect the coating to the internal ground plane. Openings are treated similarly to ensure continuity. Tests show that the enhanced plastic housing has a shielding effectiveness greater than 20 dB in the 30 MHz-1 GHz frequency band, meeting the shielding effectiveness requirements of IEC61000-5-7, and at a lower cost than all-metal housings.