Glossary

Adherence: state in which 2 surfaces are linked together through the action of external elements.

Adhesive: substance complementary to the original material allowing it to optimize its bond with another surface (acrylic adhesive mass, silicone …).

Attenuation: Natural phenomenon of energy loss of a wave during its transmission in an environment (guide, air …).

The loss of energy is also caused by the insertion of an attenuator in the transmission circuit or by the presence of shielding materials on the trajectory of the emitted wave.

Unit: dB.

Bus bar: An electrical component used to create an electrical connection. This component is used on EMI / RFI windows (conductive track in silver filled lacquer to create an electrical connection between the shielding element of the glass and the support).

Compatibility: the ability of 2 or more materials to function harmoniously in a closed or open environment without any damage to them.

Resistance to compression: force exerted to compress a material.

Compression limiter: metal insert incorporated into the seal to control its compression, limit the tightening torque and thus avoid material damage.

Electrical conductivity: unit of equipment with the capacity to transfer electricity. The electric current is measured by the volume resistivity and is expressed in ohm / cm.

Ohmic resistance: resistance to the electrical signal between 2 materials is expressed in ohm.

Corrosion: electronic degradation of the metal due to environmental aggression.

Db (decibel): measurement unit for the logarithmic ratio expression of potentials (20LogE1 / E2) or powers (10logP1 / P2).

Deflection: change of state of the material due to the compression that it can undergo.

Compression set: reduction of the thickness of a part after being put in constraint under certain conditions (load, time, temperature). Expressed in%. 

Reference standard: ASTM D 395.

Dielectric strength: maximum dielectric field that a product can undergo without breaking and measured in Kv / cm.

Hardness: measurement of the penetration of a punch in an elastomer or rubber specimen. Instrument used Durometer. Shore A degree unit (0 to 100). Reference Standard: ASTM D 2240.

E-Field: Electric field. Electrical component of an electromagnetic wave. 

Elastomer: name given to polymers with elastic properties close to natural rubbers.

Electromagnetic force: force produced by the effect of electricity and magnetism. 

EMC (Electro Magnetic Compatibility): The ability of an electronic system to operate smoothly without causing interference or degradations from external electromagnetic sources. 

EMI (electromagnetic interference): electrical interference that can affect the proper functioning of electrical and electronic equipment. Compatibility is ensured by the shielding of these equipments. 

EMP (electromagnetic pulse): short increase of the voltage, current, or small bursts of magnetic waves caused by lightning or a nuclear explosion. 

Chassis, cabinets, bays: mechanical assembly providing housing and protection of an electrical or electronic device. 

Environmental Seal: insulating gasket used to prevent contamination from air, water, or chemicals that can degrade device performance. 

Extrusion: continuous manufacturing process of linear profile. The material feeds an extruder that allows to create varied profiles by product flow between a punch and a die. 

Fluorosilicone: silicone chain with a group containing fluorine atoms. Advantage: very good chemical properties to resist to external aggressions (extreme temperatures, solvents as well as hydrocarbons).

EMI gasket: conductive material placed between 2 surfaces to ensure electrical continuity between them. For example: conductive seal providing electrical continuity between the cover and the housing of an equipment.

H Field or Magnetic: region with low impedance or magnetic components from electromagnetic sources or waves.

Hz (Hertz): International frequency unit, equal to 1 cycle / second. 

Honeycomb: hexagonal cells used in the manufacture of panels to provide ventilation functions with low resistance to air flow and efficient EMI / RFI shielding. Manufactured in aluminum or tinned welded steel. 

Loss: The difference in shielding efficiency of a tested product before and after the insertion of a vent panel with a conductive seal. 

Impedance: The total opposition offered by an electrical circuit to the conductivity of an alternating current of a single frequency. 

Interference: signal, emissions, malfunction or degraded performance of the electrical appliance. 

Monel: alloy mainly composed of nickel (67%) and copper (30%) with a low percentage of carbon, manganese, iron, sulfur and silicone. Very good corrosion resistance and high conductivity.

Polychloropene: synthetic rubber elastomer produced by the polymerization of chloroprene. Resistance to oils, oxygen, ozone, heat, oxidation light and electrical current. Commercial brand Neoprene. 

Passivation: formation of a protective layer on the surface of the metal to reduce its chemical and electrical activity during exposure in harsh environments (humidity, salt spray, etc.). 

Permeability: measure of the ability of fluids or gases to pass through a material.

Flat wave: Electromagnetic wave distant from more than one wavelength of the source where its impedance is close to that of a free space (377 Ohms). 

Adhesive Suitable for Material and Substrate Properties (PSA): Adhesive that remains viscous under normal conditions of temperature and humidity when applied to an elastomer.

Peelable protection is applied to the adhesive for handling, storage and shipping. It is easily removed during assembly on the equipment. 

RF (radio frequency): electromagnetic wave for a frequency higher than 10 KHz.

RFI: Frequency range of electromagnetic waves from 10 KHz to 10 GHz which is more limited to radio frequencies. 

Relative Conductivity: A comparison of the electrical conductivity of a material with that of silver or copper. 

Shielding effectiveness: relative measure of the effectiveness of materials and their properties under certain criteria. Measurements made before and after the insertion of a shield between the source and the reference point. This measurement is expressed in dB (decibel). Reference Standard: MIL-STD-285. 

Shielding gasket: EMC conductive gasket

Shore A: hardness measurement unit. Durometer measures the degree of hardness of materials such as rubber or plastic. Shore A hardness is applicable to elastomers. 

Silicone: Polymerized organic silicone component groups, containing a basic structure of oxygen and silicon atoms. This material makes it possible to obtain high resistance to temperatures, water, oils, etc. 

Silicone rubber: rubber polymer made from certain silicones. Maintains elasticity and electrical properties over a wide range of temperatures and is used with insulating joints … 

Surface Resistivity: measured of electrical resistance per unit area. Electrical resistance measured using a 10 cm electrode on the sides, applied on the surface of the material. Unit: Ohm squared. 

Thermal conductivity: a measure of the ability of a material to conduct heat when in contact with a hot source. Unit of measure W / m ° K or W / m ° C. 

Viscosity: Resistance of a material to the flow under stress.

Volume Resistivity: electrical resistance of a material measured per unit volume. Unit: Ohm.cm. 

Storage time limit: storage time limit for a given material and according to specific storage conditions. NFL Standards 17 104. 

Résistance rupture et allongement : mesure sur éprouvette normalisée de la force à exercer pour la rupture du matériau lors d’une traction constante. La résistance rupture s’exprime en MPa et l’allongement de la pièce à la rupture en % par rapport à la dimension initiale. Norme ASTM D 412.

Tensile strength and elongation: measurement on a standard test specimen of the force to be exerted for breaking the material during a constant tension. The breaking strength is expressed in MPa and the elongation of the piece at break in% with respect to the initial dimension. ASTM D 412 standard. 

Tear resistance: standardized specimen measurement of the force to be applied per unit of thickness to cause tearing in the direction perpendicular to the tension. ASTM D 624 standard.