EMI and RFI shielding of electronic devices can be critical to their reliability and safety. Proper protection and shielding are vital in many challenging industries including aerospace, medical devices, and transportation. In addition to shielding, grounding of devices as well as protection from galvanic corrosion can extend service life and reliability. Chase Corporation has developed a unique line of preformed gasketing and shielding materials that can combine to serve the multiple functions of shielding, grounding, and corrosion resistance within a single material.

A Quick Definition of EMI and RFI Shielding

So, the first question that probably needs to be answered is simply, What is EMI and RFI shielding and why is it important? EMI stands for electromagnetic interference and RFI stands for radio frequency interference. The two terms have some overlap and in reality, only the term EMI truly matters, since radio frequencies are part of the electromagnetic spectrum.

Many modern devices contain highly sensitive components and processors that rely on tightly controlled currents and voltages to function properly. In addition, the use of high-frequency sensors that transmit and receive radio frequencies are becoming ubiquitous in markets such as EV and autonomous driving. There are many ambient as well as man-made sources of electromagnetic and radio waves, and these can interfere with devices, leading to errors and failures. This is of course absolutely unacceptable in critical areas such as medical products, automotive products, and within the aerospace and military industries.

In order to protect electronics from outside and unwanted interference, the most common solution is to completely encase the device or cable in a conductive layer that will absorb and carry away unwanted EM and RF interference. This concept was established as essentially a Faraday cage and has been improved upon ever since.

What Are the Various Functions of EMI Gaskets?

There are essentially four main potential needs that can be addressed through EMI shielding and gasketing materials:

• EMI Shielding

High-performance and high-frequency devices require conductive layer shielding against ambient as well as power issues. These can include magnetic fields and interference, such as welders, solar interference, power sags or spikes, lightning, and so forth.

• Galvanic Corrosion Protection

Through electric charge dissipation, which results in protection and added longevity against corrosion in areas including aircraft skin and antennas, among others. 

• Environmental Sealing

The basic function of gaskets is to provide protection from the ingress of environmental fluids and gases.

• Grounding

The need for electrical fortification can be met with conductive grounding pathways.

A Versatile Approach

The older and more traditional approach to EMI gasketing and sealing involved the cutting and forming of metal parts and gaskets. These products in most instances served the purpose of shielding and potentially grounding. They were, however, inefficient and ineffective in the long-term prevention of fluid ingress and corrosion protection.

A newer and more robust approach is the use of flexible polymers such as silicones, which can be filled with conductive materials or built with a metal screen internal lattice. The metal screen lattice approach tends to be the preferred method as it provides a consistent structure compared to heavily filled silicones, which can have an uneven filler composition.

One EMI Gasket -- Multiple Protective Functions

The use of wire mesh encased in silicone polymer as an EMI shielding and gasketing material provides a product that can serve multiple purposes such as can be seen in the drawing below. The silicone polymer affords a flexible and durable seal against environmental conditions including ingress of liquids and vapors. The conductive wire mesh delivers reliable EMI shielding against man-made and environmental electrical interference or disruption.

As a supplier of electronics protection polymers and coatings, Chase Corporation and our employees can help you with a comprehensive and unbiased approach to evaluating your application and process. We’ll show you how to maximize efficiency, minimize cost, and improve product reliability. Our outstanding manufacturing and technical support groups can provide your organization with reliable global supply, unmatched quality, and superior technical support.

Please contact us today to discuss your application.