Product Summary

WaveZero's Flow/Met™ is a unique shielding product that allows airflow through its structure while providing EMI/RFI shielding. Flow/Met™ was created to allow product teams with a method for maintaining cooling airflow through chassis fan vents while preventing EMC compliance issues associated with unshielded openings in the chassis. Flow/Met™ is created using a polymer based reticulated foam that has a vapor deposited layer of 99.5% pure aluminum. The metallization layer is 0.5 micrometer on the external surfaces of the foam cells. The resultant material is very light, can be created in number of densities to facilitate the required airflow, and has excellent shielding characteristics across a wide range of frequencies.

Flow/Met™ can also be used as an EMI shield compressed between two metallized surfaces. In this application, the "sandwiched" layer of foam provides excellent EMI shielding while minimizing weight.

The metallized foam is structurally stable and there is excellent adhesion of the aluminum layer eliminating "rub off" particles associated carbon treated foam.

Technical Data (1.04 MB)

Design Flexibility

WaveZero creates innovative shielding solutions that provide design teams maximum flexibility and rapid time-to-market. The Flow/Met™ solution is a perfect example. Designers select the thickness of the material, the pore density (number of pores per inch -PPI), and the physical configuration of the product.

Let's say the application requires light-weight emi shielding between two 10"x10" aluminum panels with a 1/2 '" gap between them. The selection could be for a 3/4" thick Flow/Met™ with 45 PPI that is 10"x10". The foam would be compressed between the two panels.

In a single fan vent application, the optimal Flow/Met™ shielding selection might be a 4"x4" square with1/4" thickness and 10 PPI for maximum airflow. If the chassis contained two fans side by side, the Flow/Met™ EMI shield could be 4"x 8" with 1/4" thickness and 10 PPI.

Environmentally Sound

Flow/Met™, like all WaveZero products, is environmentally friendly in that no volatile organic compounds (VOC's) are involved in the process; additionally, the products are readily recyclable.

The recorded EMI shielding effectiveness data for Flow/Met™ when used as an EMI air filter is displayed below. The less dense 10 PPI, Flow/Met™ material was tested in this application for its superior airflow characteristics. The test procedure involved shielding a square opening in an anechoic test chamber with Flow/Met™ material. The RF emission measurements were compared against measurements recorded from the same square opening when left unshielded. Shielding effectiveness varied from 55 dB to 92 dB, depending on frequency and porosity.

FLOW/MET™ Shielding Effectiveness When Used As an EMI Air Filter

WaveZero's data on the shielding effectiveness of Flow/Met™, when used as an EMI air filter, is displayed below. The less dense 10 PPI Flow/Met™ material was tested in this application for verification of its superior airflow characteristics. The test procedure involved shielding a square opening in an anechoic test chamber with Flow/Met™ material. The RF emission measurements were compared against measurements recorded from the same square opening left unshielded. Shielding effectiveness varied from 55 dB to 92 dB depending on frequency and porosity.

FLOW/MET™ Air Flow Properties

This graph shows typical airflow properties for Flow/Met™ products of varying porosity when subjected to different airspeeds.

FLOW/MET™ Shielding Effectiveness Under Compression

This graph depicts data on the shielding effectiveness of Flow/Met™ while under compression. Flow/Met™ materials of greater density, 30 and 45 PPI, were tested in this application for the increased metalized surface area. The test procedure involved compressing Flow/Met™ shielding material with a solid steel plate over a square opening in an anechoic test chamber. The RF emission measurements were compared against measurements recorded without any compressible materials between the steel plate and the anechoic test chamber. Shielding effectiveness varied from 58 dB to 90 dB, depending on frequency and porosity.

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