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EMI RFI Shielding

What are EMI & RFI Shielding Coatings?

EMI or RFI affects an electrical circuit by either electromagnetic induction or electromagnetic radiation. EMI/RFI protective coating can help address the issue of interference.

EMI:  Electromagnetic Interference

RFI:  Radio Frequency Interference

Plastic components may need EMI or RFI shielding to function properly and avoid interference from other devices. Adding the right coating (such as aluminum, copper, and zinc) could make all the difference. These coatings can be applied to fiberglass and polycarbonate electronic enclosures.


The benefit of EMI and RFI shielding is the prevention of malfunction of the electronic device from the interference of outside signals and the electrical noise associated with the operation of electronic equipment.  

Control Box with EMI RFI shielding

Applications Include:

  • Medical Devices

  • Radios

  • Computers

  • Mobile Phones

  • Marine Electronics

  • Military Applications

  • Control housings, Boxes, & Covers

Why Wet Spray Coatings?

Industrial spray painting allows a metered amount of the shielding material to be deposited evenly across every section and contour of the part, down to the smallest cracks and crevices. The spray process provides consistency to ensure quality, minimizing costs, and meeting all necessary requirements.

Masking is a critical aspect of the spray coating process. Anywhere that shielding is not required must be masked from the spray, which can include corners, through holes, and screw threads. Masking can be carried out by hand, using tape, plugs, or custom fixtures.

Tooling and fixtures can be designed to hold the part, allowing for maximum accuracy and consistency of the final product, as well as increasing production efficiency throughout the process.

EMI Reasons

3 Reasons a Plastic Part May Need EMI Shielding

1. Signals: For any device that emits a communication signal, it is imperative to protect the outward signal flow to ensure proper performance. EMI shielding can protect the electronic signals, allowing them to function more freely from interference from outside sources.

2. Multiple Device Parts: With our current technology growing and changing, working independently as well as interdependently, too many uncontrolled signals can cause interference, causing communication and functional errors. With proper EMI shielding, every part of the device can deliver its signals correctly.

3. Outside Interference: As our electronic footprint grows, more devices in close proximity will likely have trouble dealing with the differing interfering signals. EMI shielding removes this problem by limiting the pathways for the foreign signals to interfere. This allows the device to perform with maximum efficiency in the presence of competing devices.

Plastic cover with professional EMI RFI shielding
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