Advanced technology, high quality products
and in-depth application expertise combine
to provide cost effective solutions
to EMI/RFI shielding challenges.

Knit Shield
The Knit Shield product line consists of  various forms of metal knitted wire mesh or wire mesh fabricated over an elastomer core thus serving as both an EMI/RFI gasket shield and a limited environmental seal.  Knit Shield is commonly used  in electronic enclosures where low closure force is required with low compressibility set.  Elastomer core products are typically an economical way to shield large gaps.  Standard Knit Shield cross-sections are rectangular, round, round-with-fin, and double-round-with-fin. The mesh consists of many interlocking loops that act as thousands of small springs which provide for a resilient all-metal conductive gasket.  When an elastomer is the core for the wire mesh, it provides excellent compressibility with a high degree of resilience while, at the same time, functioning as an environmental seal..

  

 


Knit Shield gasket performance
The metal mesh construction provides excellent EMI/RFI protection because of the metal-to-metal contact and the ability of the mesh to cut through surface films on mating surfaces, thus reducing surface resistivity to micro-ohm-centimeter levels. The continuity of the knitted mesh wire gives the gasket high internal conductivity, as well. The inherent resiliency of the knitted mesh makes it ideal for applications in sheet metal enclosures.  The elastomer core provides a seal against rain, ventilated air, dust and other environmental contaminants. Additional performance, tolerance, and material data, click here.

Knit Shield gasket materials

Knit Shield gaskets are constructed of knitted wire mesh strips which are calendered to close tolerance cross-sections.  The metal mesh material can be Monel (nickel-copper alloy) , SnCuFe ( tin-plated copper-clad steel), tin-plated phosphor bronze, aluminum, or stainless steel.  The most common wire materials are Monel, which combines excellent EMI/RFI protection, high tensile strength and resiliency, and high resistance to oxidation, and SnCuFe, which offers best shielding performance at lower frequencies, especially with respect to magnetic fields.  Aluminum mesh is occasionally used when the mating surfaces are aluminum.  Any metal wire can be fabricated into a Knit Shield mesh gasket depending on the customer's requirements. Choices for elastomer materials are neoprene sponge, neoprene solid, silicone sponge, silicone solid, and others.

Knit Shield  gasket mounting

Typically rectangular and round cross-section gaskets are mounted into a channel.  The channel holds the gasket in place by sidewall friction and prevents the gasket from being over compressed.  Alternatively the gasket is held in place in tight fitting slots or bonded in place using an adhesive. Single-round gaskets-with-fin and double-round gaskets-with-fin are held in place by clamping the fin section down under a metal strip, using an adhesive, or by riveting, spot-welding or adhesive bonding.  Both rectangular gaskets and round-gaskets-with-fin can be supplied with attached pressure sensitive adhesive tape to ease installation.

Knit Shield gasketing selections and How to Order
Gasket cross-sections, round and round-with-fin, are available in diameters from .062" to 1".  Rectangular cross sections are available in sizes from .062" to 1" square. Metal strip gaskets come both with an elastomer sponge core and as an all-metal strip gasket.  All are available on spools of any continuous length. To view the Knit Shield Metal Strip Gasket Selection Guide, click here.  To order, specify the part number from the appropriate selection table and state the length required. For other sizes and/or materials not shown in the tables, consult our Applications Engineering Department at Tel: (508) 880-0987 • Fax: (508) 880-0334 or E-mail: sales@shielding.com, tech-info@shielding.com

Typical Shielding Effectiveness of Knit Shield (tests based on MIL-STD 285)

Frequency Field       Attenuation (dB)  
    SnCuFe Monel  Aluminum
10 KHz H 44 38 32
100 KHz H 62 51 45
1 MHz H 79 66 56
1MHz E 116 114 100
10 MHz E 115 112 97
100 MHz E 107 102 92
1 GHz Plane Wave 94 89 76
10 GHz Plane Wave 68 64 56

Wire Specifications:
Monel wire - QQ-N-281, Class A, .0045" dia. std.
SnCuFe wire - ASTM B 520, .0045" dia.std.
Aluminum wire - AMS 4182, Alloy 5056, .005" dia.std.
Stainless Steel wire - Alloy 304, .0045", .0060" dia.std.
Other wire diameters available.

Elastomer Specifications:
Neoprene Sponge - MIL-R-6130 B, Type. II, Grade A, Condition medium
Neoprene Solid - MIL-R-6855, Class II, Grade 40
Silicone Sponge - AMS-3195
Silicone Solid - ZZ-R-765, Class 2B, Grade 40

 


 Product Categories
I Shielded Optical Windows I
 I Oriented Wire Shield and Seal I Foil Shield and Seal
 I
 I
Woven Shield and Seal
 I Thermally Conductive Materials I
  I Frame Shield
 I Knit Shield I Knit Shield and Seal I Knit Shield Wrap I
  I Particle Filled Conductive Silicone Gasketing I Shielded Air Ventilation Panels I

  
I Shielded Screen Filter Ventilation Panels I Conductive Caulking & Adhesives I
  I Knit Shield Ring and Contact Buttons I


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Shielding Express Inc.
29 Mozzone Blvd. • Taunton, MA 02780 USA
Tel: (508) 880-0987 • Fax: (508) 880-0334
E-mail: sales@shielding.com
       tech-info@shielding.com