Precision Die-Cut Components

EMI/ESD Shielding Laminates

Shielding and grounding improvements over conductive coatings.

Laminates of metal foil and dielectric film provide EMI protection and ground planes at both board and enclosure levels. When properly grounded, a laminate's foil layer provides 10-60 dB of EMI shielding at 1 MHz - 1 GHz. This equals or surpasses shielding performance obtained from conductive coatings. The film layers provide insulation, scratch and puncture resistance, flame resistance and flexibility.

Laminate shields and ground planes can include die-cut shapes, edges, and holes for custom fitting intricate packages. Scoring provides extensive folding options including six-sided enclosure shapes. PressCut laminates commonly feature specific areas of exposed foil. Typically, these are integral grounding tabs used for component grounding.

The dielectric film layer on laminate shields provides electrical insulation and protection, which is not offered by other methods. This feature prevents component shorting upon contact with the shield. PressCut's standard foil and film laminates are UL listed at either 94 V-1 or V-0.

ESD (electrostatic discharge) is the release of a stationary electric charge on objects such as electronic keyboards. Discharges can occur when a static charge builds up across gaps up to 0.3 inch (7.6mm). ESD can reach 25,000 volts, which is enough to interfere with operations or destroy critical circuit components.

ESD arcing to a printed circuit board results in high currents induced through traces on the board. This can cause false data to be generated or damage to board components. Radiated upsets occur when static discharges to a metal object, causing the generation of EMI. With proper grounding, PressCut foil and film laminates provide protection from ESD transients as high as 25,000 volts. The metal foil component provides grounding of ESD currents and will also carry currents as an EMI shield.

PressCut Industries offers a complete line of EMI/ESD shielding laminates. Our laminate materials can be custom formulated to meet any requirement. Pick the combination of properties associated with the various materials listed on the tables below to produce a laminate that meets your needs.

Step 1: Choose the foil that meets your requirements from Table 1.

Table 1 Mechanical Properties Electrical Properties
Product Description Foil Thickness Total Thickness Breaking Strength Sheet Adhesion Electrical Resistance through Adhesive
Dead soft aluminum foil tape with an electrically-conductive pressure sensitive adhesive. 0.0020 in
(0.051 mm)
0.0032 in
(0.081 mm)
18.0 lb/in
(31.5 N/10 mm)
35.0 oz/in
(3.8 N/10 mm)
0.010 ohm
Dead soft copper foil tape with an electrically-conductive pressure sensitive adhesive. 0.0014 in
(0.034 mm)
0.0026 in
(0.066 mm)
25.0 lb/in
(43.8 N/10 mm)
35.0 oz/in
(3.8 N/10 mm)
0.005 ohm

Step 2: Choose the dielectric film from Table 2 and whether it needs to be laminated to one or both sides of the foil.

Table 2 Typical Values
Properties PVC Polyester Polypropylene Nomex®
Water Absorption
% Change in Weight
(ASTM D-570)
0.40% 0.80% 0.01% 9.00%
Dielectric Strength
Volts/Mil
(ASTM D-149)
1100 7500 2200 860
Dielectric Constant
(ASTM D-150)
4.0 3.0-3.7 2.3 2.4
Dissipation Factor
(ASTM D-150)
0.0090 0.0050 0.0019 0.0060
Volume Resistivity
ohm-cm
(ASTM D-257)
1015 1018 3.97 x 1015 1016
Flammability V-1 VTM-1 VTM-0 V-0
Thickness Availability .003 inch
.006 inch
.010 inch
.003 inch
.005 inch
.007 inch
.005 inch
.010 inch
.017 inch
.005 inch
.010 inch

Note: Insulation materials can be applied to one or both sides of foil as required.

For design assistance, contact the sales department at PressCut Industries.

Nomex® is a registered trademark of E.I. DuPont de Nemours & Co.