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What to Know About Photochemical Etching for EMI/RFI Shielding

Electronic and radio devices naturally emit electric signals and radio waves that could interfere with other devices. If this interference isn’t stopped, malfunction and even disaster can take place for the devices people use on a daily basis. 

Electromagnetic interference (EMI) and radio frequency interference (RFI) are any interferences that come from electronic and radio devices. For example, a smartphone regularly produces electromagnetic waves that could conflict with nearby technology.

If you’re answering a call in a hospital room, your smartphone could interfere with the vital, life-saving medical devices inside the room. EMI and RFI shielding protects technology from these interferences, and a key process in manufacturing these components is photochemical etching. 

In this article, we’ll discuss everything you need to know about photochemical etching to produce custom EMI shielding for any application. 

Etched EMI/RFI Shielding

EMI/RFI shielding is the process of reducing the electromagnetic and radio signals radiating from electronic devices. This is done by using thin sheets of metal and placing them around a device’s most sensitive zones, using seals or shielding gaskets. 

The goal of EMI RFI shielding is to create electromagnetic compatibility (EMC), which is the ability for all electronic devices to work properly in their environments. 

These metals act as a Faraday cage, creating attenuation that keeps electromagnetic radiation inside the device and prevents interference from escaping it. There are several types of manufacturing techniques commonly used to etch EMI/RFI shielding and improve electrical conductivity.

These are:

  • Adhesive Bonding: This is the process of using resins and coatings that contain conductive elastomers that can discharge the currents around them. Epoxies and silicone are mostly used in this process to fill the enclosures in electronic devices. Conductive adhesives are ideal for handheld devices, such as tablets and cell phones. 
  • Vacuum Deposition: Vacuum deposition involves coating a device with conductive metal using evaporation at levels much lower than atmospheric pressure. This process is ideal for creating cost-effective shielding parts with varying coating density levels. 
  • Laser Cutting: This manufacturing process uses a superheated laser to cut shapes out of metal sheets. Laser cutting is ideal for creating precise, small-batch shielding orders.
  • CNC Machining: This is an automated process whereby a machine dictates the movement of blades to cut metal sheets into desired shapes. Because this process involves a machine, it’s popular for producing a large number of parts that have the same ISO specifications.  
  • Stamping: This manufacturing process involves using substantial pressure to shape metal sheets into suitable shielding parts. This is another process that’s ideal for producing a large quantity of shielding parts. 
  • Photochemical Etching: This is the process of using a photoresist chemical to dissolve away the unwanted parts of a metal sheet to form electronic components. This is the most versatile method for producing shielding parts in high volume without the threat of damage from heat or pressure. 

Photochemical etching is a top choice for many manufacturers. This is because this process does not use substantial force or heat to shape metal sheets into EMI and RFI shielding. 

For example, laser cutting produces extreme heat that can damage metal and cause burrs to form. Photochemical etching eliminates this risk and is a low-cost option for producing shielding in any batch size. 

Elcon Precision specializes in implementing photochemical etching with the highest standards of precision and quality. Whether you need a small production run or a large batch, we have the technology and resources to complete your project according to your specifications. 

Material Selection for EMI/RFI Shielding Projects

When it comes to EMI/RFI shielding materials, not all materials are created equal. Some materials are not conductive enough and can compromise the entire shielding process. Others are unable to resist the harsh environmental conditions necessary to improve shielding effectiveness.

As a result, the most common materials used in EM/RF shielding projects are:

  • Conductive fabrics
  • Conductive foam
  • Foils and foil tape

The standard base metals used for photochemical etching are:

Nickel-silver is usually the metal of choice, mainly because it’s an excellent conductor and doesn’t require any additional finishing due to its high solderability. 

The material and metal you choose for your project will ultimately depend on your budget, project design, and application requirements. 

Common EMI/RFI Shielding Applications

EMI/RFI shielding is used in various industries where electronic use is pivotal for production. Some of the most common EMI/RFI shielding applications exist in:

  • Aerospace: EMI/RFI shielding ensures optimal high-frequency radio and electronic functions for devices such as infrared sensors, electrical circuits, and ion thrusters. 
  • Medical: Medical instruments keep injured and recovering patients alive and well. EMI/RFI shielding is an essential electric component of keeping these devices operational and able to exist cross-functionally with other machines. 
  • Defense: EMI/RFI shielding ensures crystal-clear radio frequencies that guide the operations of missile guidance systems, long-range radar systems, and other key defense systems. 
  • Space-Flight: Much like aerospace machines, any device that leaves Earth’s orbit needs to contain EMI/RFI shielding components to ensure proper frequency and internal operations. 
  • Energy: From solar panels to thermoelectric generators, all machines that produce energy need to be protected from incoming EMI and RFI. 

Designing Your EMI/RFI Shielding

One of the most important elements in EMI/RFI shielding is the design. Smartphones, radios, and other devices that emit EMI and RFI couldn’t be any different from each other. As such, each of these devices requires unique shielding designs.

In fact, the design you ultimately use can impact the entire performance of a product. For example, the use of laser cutting may work for precise designs. However, laser cutting may not be suitable for projects that require large batches of delicate designs.

Because of this, it’s important to work with a reputable manufacturer that delivers highly customizable for your EMI/RFI shielding projects. For example, Elcon Precision can incorporate bend lines that can save you hundreds of dollars in NRE tooling costs.

Trust Elcon Precision to Deliver High-Quality Shielding Products

Overall, EMI/RFI shielding eliminates the possibility of interference from one electronic device to another. When choosing shielding solutions, there are many factors to consider, such as the shield design, your budget, and the application requirements for the conductive materials you’re using. 

If you’re ready to explore your options for photochemical etching and EMI/RFI shielding, request a quote today to receive more information.

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