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Electromagnetic Interference (EMI)/Radio Frequency
Interference (RMI) Shielding Products
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Engineers designing electronic instruments many
times must manage electromagnetic interference (EMI)
that may cause an undesirable response, malfunctioning
or degradation in the performance of electrical
equipment. Electromagnetic interference (EMI)
shielding is the process of blocking the induction of
electromagnetic radiation, which is emitted by
electrical circuits carrying rapidly changing signals,
as a by-product of their normal operation to other
circuits which causes unwanted signals (interference
or noise). This is achieved by separating the circuits
with a barrier made of conductive material. One of
the best ways to protect from unwanted emissions is to
contain the noise within an enclosure. The enclosure
lid needs to make good contact with the enclosure
itself to create a complete conductive path.
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J.J. Short Associates, Inc. has
several materials available to be custom molded or die
cut into EMI shielding shapes and gaskets. As with our
other product lines, J.J. Short Associates, Inc.
offers custom designed, EMI-Shielded O-rings, seals
gaskets and molded sheet stock for a variety of
electronic applications from prototype to production,
in small lots or long runs. Our EMI shielded O-rings
and seals provide moisture/pressure sealing and
EMI/EMP shielding when compressed in a properly
designed groove. They are interchangeable with
standard non-conductive seals of the same dimensions
or designed to meet your exact specifications and
dimensions.
J.J. Short Associates, Inc. offers conductive
O-rings and seals utilizing commercial grade and
military grade shielding elastomers and can produce
EMI-Shielded seals and gaskets in an unlimited variety
of shapes and sizes.
There are many types of EMI shielding materials and
solutions available to the engineer. Conductive
elastomers are an extension of our rubber
capabilities. We can provide EMI parts and gaskets
that are compression molded, die cut, or water jet cut
from electrically conductive silicone rubber
compounds. The main advantage of EMI shielding
gaskets, seals and parts fabricated from conductive
elastomers is the combined benefit of environmental
sealing over a broad temperature range and EMI
shielding. This conductive material is typically
silicone rubber or fluorosilicone rubber with embedded
silver plated aluminum particles, silver plated glass
beads, silver plated copper particles, nickel-graphite
particles or conductive carbon.
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Many of our line of conductive silicone elastomers are
designed around the Mil-DTL-83528C Specification.
A partial listing of our compounds include:
Custom Conductive Elastomers Mil-G-83528 Qualified and
Commercial Materials
Type A = Silver (Ag) coated Copper (Cu) in Silicone 65
Shore A Type B = Silver (Ag) coated Aluminum (Al) in
Silicone 65 Shore A Type C = Silver (Ag) coated Copper (Cu)
in Fluorosilicone 75 Shore A Type D = Silver (Ag) coated
Aluminum (Al) in Fluorosilicone 70 Shore A Type E = Silver
(Ag) in Silicone 65 Shore A Type F = Silver (Ag) in
Fluorosilicone 75 Shore A Type G = Silver (Ag) coated
Copper (Cu) in Silicone 80 Shore A Type H = Silver (Ag) in
Silicone 80 Shore A Type J = Silver (Ag) in Silicone 45
Shore A Type K = Silver (Ag) coated Copper (Cu) in Silicone
85 Shore A Type L = Silver (Ag) coated Nickel (Ni) in
Silicone 75 Shore A Type M = Silver (Ag) coated Glass in
Silicone 65 Shore A Nickel and Nickel coated Graphite (30
Shore A to 75 Shore A) in Silicone
Our conductive materials are used to produce shielding
gaskets, seals, condiuctive o-rings, sheets and molded shapes
for Military, Aerospace, electronics, and communications
applications. Our range of conductive elastomers has expanded
to include materials that are designed to balance requirements
for electrical conductivity and cost performance for the
commercial sector.
Some Common Questions Regarding Qualifying EMI/RFI
Shielding Material
- What is the max ohms/cm in terms of volume resistivity
do you need to achieve?
- What is the max ohms/cm in terms of surface
resistivity you need to achieve?
- What environment will this material be exposed to? Or
does this need to be a solvent resistant or
fluorosilcione?
- Does this material need to meet the Mil-Dtl-83528C QPL
spec? If yes what type or call out? (the specs go from
type A to type M)
- Are you looking for a semi conductive or static
dissipating material or is this a true EMI/RFI shielding
application?
- What thickness do you need and at what thickness
specification in terms of +/-
Contact us
with your sketches, drawings and specifications and we will
see if we can help!
If it's made from rubber,
contact us!
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