DESCRIPTION: CHO-SHIELD covers are a unique, labor-saving solution for providing EMI
shielding and gasketing, as well as circuit-to-circuit cross talk isolation, within electronic
enclosures. The CHO-SHIELD cover features custom designed, glass fiber-reinforced polyester plastic, with an integrally molded conductive elastomer as the EMI shield. The elastomer is molded onto both the inside surface of the cover and its side walls, to provide an integral EMI shield. The elastomer can also be molded to form interior walls that provide electromagnetically isolated (shielded) compartments between potentially interfering circuitry.
CHO-SHIELD shielding covers eliminate the need for conductive paints, coatings or platings on plastic covers. They also replace the labor-intensive installation of EMI gaskets to prevent EMI leakage at seams and achieve circuit-to-circuit isolation. They are lightweight, easily installed, and reusable. Metallic inserts can be incorporated to allow easy installation with screws. The standard conductive elastomer used is Chomerics’ popular CHO-SEAL 1310 silver-plated-glass filled silicone elastomer. This material provides >60 dB shielding effectiveness from 200 MHz to 10 GHz. Other conductive elastomers, including CHO-SEAL 1273 and CHO-SEAL S6304, are available for higher shielding values or other properties. Typical elastomer thickness on the face of the plastic cover is 0.020 inch (0.5 mm). Thickness at the distal edges of internal cover walls and ribs is typically 0.070 to 0.125 inch (1.78 to 3.18 mm), providing a resilient, low impedance seal against enclosure walls and flanges.
