Page 7 - EEC_EMI Tech Guide
P. 7
I/RFI
System EMI/RFI Performance
Long-term Performance Metals Compatibility
Long-term performance should be a major factor in your enclo- To avoid galvanic action between metals that contact each other,
sure selection. An enclosure that develops leaks over time may refer to the chart below. Each group overlaps, making it possible
become apparent only after other system problems develop from to use materials from adjacent groups safely.
stray signals. Investing in an enclosure that has been designed for Group 1 (Metal Groupings)
long-term performance will result in fewer problems in the Gold Platinum Gold/Platinum Alloys Rhodium Graphite
future. Three significant factors affect the long-term performance Palladium Silver Silver Alloys Titanium
of a shielded enclosure: Group 2 (Metal Groupings)
Rhodium Graphite Palladium Silver Silver Alloys
Enclosure Design – The basic design of the sheet metal Titanium Nickel Monel Cobalt Nickel and Cobalt Alloys
components should contribute to shielding performance. Nickel Copper Alloys AISI 300 Series Steels A286 Steel
Equipto Electronics’ Heavy Duty enclosures serve as the Group 3 (Metal Groupings)
basis for our shielded enclosures and provide a significant Titanium Nickel Monel Cobalt Nickel and Cobalt Alloys
level of shielding, even without gaskets, due to the double Nickel Copper Alloys Copper Bronze Brass Copper
ledge, double plane construction of the frame, flush side Alloys Beryllium Copper Silver Solder Commercial Yellow
panels and door design. The inherent design characteristics of Brass and Bronze Leaded Brass and Bronze Naval Brass
the Heavy Duty frame allow it to be adapted easily to addi- 400 Series Stainless Steel Chromium Plate Tungsten
tional gasket and door configurations and its strength makes Molybdenum
it adaptable to other dynamic performance requirements. Group 4 (Metal Groupings)
Leaded Brass and Bronze Naval Brass Steels AISI, 431, 440,
Materials Compatibility – Because shielded enclosures must 410, 416, 420, AM 355, PH hardened Chromium Plate
be electrically conductive to operate effectively, using dis- Tungsten Molybdenum Tin-Indium Tin Lead Solder Lead
similar materials can cause corrosion and loss of shielding Aluminum 2000/7000 Series Alloy and Carbon Steel
performance. The corrosion is an electro-chemical reaction Group 5 (Metal Groupings)
between the two dissimilar metals which significantly Chromium Plate Tungsten Molybdenum Steels AISI, 410,
impairs the electrical conductivity between the two metals 416, 420, Alloy and Carbon Tin-Indium Tin Lead Solder
and is a cause of leaks that develop over a period of time. Lead Aluminum All Aluminum Alloys Cadmium Zinc
The easiest to way to control galvanic corrosion is to specify Galvanized Steel Beryllium Zinc Base Castings
enclosures that use materials that are as galvanically similar Group 6 (Metal Groupings)
as possible. Materials used in Equipto Electronics shielded Magnesium Tin
enclosures have been carefully specified to provide the best
possible compatibility and durability. Plated frames and pan- In the Standard Shielding method,
els are not used, due to susceptibility to damage in the manu- Panels and Doors fit into the
facturing or the system building process as well as compati-
bility issues. recessed ledges of the frame with
beryllium copper spring-finger
Gasket Durability – In addition to frame design and frame gasketing, assuring
material compatibility gasket materials must be carefully high-shielding effectiveness.
specified. Since the gasket is a critical component in assur-
ing electrical conductivity between removable panels and In the Double Shielding or combina-
doors, its profile is also critical. tion of EMI/RFI shield and dust and
moisture gasket, the dust and moisture
Materials – are they galvanically compatible? The gasketing is easily added at the panel
gasket/enclosure electrical conductivity must be seams and door for protection in the
maintained in order for the enclosure to provide sus- harsh environments of factory and
tained acceptable attenuation. Equipto Electronics field applications.
has taken special care to utilize materials that are gal
vanically compatible and specified for long-term
use. While all dissimilar materials will have some
corrosive effect on each other, materials used in our
EMI/RFI cabinets produce the least amount of dete-
rioration of any readily available group of materials.
6 Equipto Electronics Corp. Aurora, IL 800.204.7225 630.859.7840 Fax 630.897.5314
System EMI/RFI Performance
Long-term Performance Metals Compatibility
Long-term performance should be a major factor in your enclo- To avoid galvanic action between metals that contact each other,
sure selection. An enclosure that develops leaks over time may refer to the chart below. Each group overlaps, making it possible
become apparent only after other system problems develop from to use materials from adjacent groups safely.
stray signals. Investing in an enclosure that has been designed for Group 1 (Metal Groupings)
long-term performance will result in fewer problems in the Gold Platinum Gold/Platinum Alloys Rhodium Graphite
future. Three significant factors affect the long-term performance Palladium Silver Silver Alloys Titanium
of a shielded enclosure: Group 2 (Metal Groupings)
Rhodium Graphite Palladium Silver Silver Alloys
Enclosure Design – The basic design of the sheet metal Titanium Nickel Monel Cobalt Nickel and Cobalt Alloys
components should contribute to shielding performance. Nickel Copper Alloys AISI 300 Series Steels A286 Steel
Equipto Electronics’ Heavy Duty enclosures serve as the Group 3 (Metal Groupings)
basis for our shielded enclosures and provide a significant Titanium Nickel Monel Cobalt Nickel and Cobalt Alloys
level of shielding, even without gaskets, due to the double Nickel Copper Alloys Copper Bronze Brass Copper
ledge, double plane construction of the frame, flush side Alloys Beryllium Copper Silver Solder Commercial Yellow
panels and door design. The inherent design characteristics of Brass and Bronze Leaded Brass and Bronze Naval Brass
the Heavy Duty frame allow it to be adapted easily to addi- 400 Series Stainless Steel Chromium Plate Tungsten
tional gasket and door configurations and its strength makes Molybdenum
it adaptable to other dynamic performance requirements. Group 4 (Metal Groupings)
Leaded Brass and Bronze Naval Brass Steels AISI, 431, 440,
Materials Compatibility – Because shielded enclosures must 410, 416, 420, AM 355, PH hardened Chromium Plate
be electrically conductive to operate effectively, using dis- Tungsten Molybdenum Tin-Indium Tin Lead Solder Lead
similar materials can cause corrosion and loss of shielding Aluminum 2000/7000 Series Alloy and Carbon Steel
performance. The corrosion is an electro-chemical reaction Group 5 (Metal Groupings)
between the two dissimilar metals which significantly Chromium Plate Tungsten Molybdenum Steels AISI, 410,
impairs the electrical conductivity between the two metals 416, 420, Alloy and Carbon Tin-Indium Tin Lead Solder
and is a cause of leaks that develop over a period of time. Lead Aluminum All Aluminum Alloys Cadmium Zinc
The easiest to way to control galvanic corrosion is to specify Galvanized Steel Beryllium Zinc Base Castings
enclosures that use materials that are as galvanically similar Group 6 (Metal Groupings)
as possible. Materials used in Equipto Electronics shielded Magnesium Tin
enclosures have been carefully specified to provide the best
possible compatibility and durability. Plated frames and pan- In the Standard Shielding method,
els are not used, due to susceptibility to damage in the manu- Panels and Doors fit into the
facturing or the system building process as well as compati-
bility issues. recessed ledges of the frame with
beryllium copper spring-finger
Gasket Durability – In addition to frame design and frame gasketing, assuring
material compatibility gasket materials must be carefully high-shielding effectiveness.
specified. Since the gasket is a critical component in assur-
ing electrical conductivity between removable panels and In the Double Shielding or combina-
doors, its profile is also critical. tion of EMI/RFI shield and dust and
moisture gasket, the dust and moisture
Materials – are they galvanically compatible? The gasketing is easily added at the panel
gasket/enclosure electrical conductivity must be seams and door for protection in the
maintained in order for the enclosure to provide sus- harsh environments of factory and
tained acceptable attenuation. Equipto Electronics field applications.
has taken special care to utilize materials that are gal
vanically compatible and specified for long-term
use. While all dissimilar materials will have some
corrosive effect on each other, materials used in our
EMI/RFI cabinets produce the least amount of dete-
rioration of any readily available group of materials.
6 Equipto Electronics Corp. Aurora, IL 800.204.7225 630.859.7840 Fax 630.897.5314
