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What You Must Know About the Use of EMI Shielding Materials in the Medical Industry

What You Must Know About the Use of EMI Shielding Materials in the Medical Industry
May 2, 2018 Simon Hopes

Sophisticated medical instruments must operate seamlessly in noisy hospital surroundings, including a doctor’s clinic. Now, this is one problem identified as a primary concern by the federal government, medical equipment designers, and industry associations, as electromagnetic radiations emanating from each device affect the performance of sophisticated medical equipment in healthcare facilities. The increasing demand for lightweight, compact, and portable devices made suppliers look for injection-molded plastic to comply with the design requirements. However, such components are not good at minimizing or eliminating the radiations from being emitted from devices or entering medical electronics. The solution lies in the use of EMI shielding systems that are included to ensure optimal machine performance, patient safety, and compliance with regulatory guidelines.

If these emissions are not controlled or eliminated with the use of EMI shielding materials, conflicting electromagnetic energies emanating from different devices will affect patient safety in medical facilities.  Various radiation sources include computer circuits, electric motors, cable lines, and even fluorescent lights. When sensitive medical devices are affected by EMI, the results can prove life-threatening for your patients. For instance, a person under ventilation in your hospital may start facing breathing issues because of harmful interference. No matter whether patients are in their cabins or the operation theater, shielding engineers should make patient- safety the top priority while designing EMI shielding products. Here are a few points you must know if you are on the lookout for a suitable shielding solution for your medical device.

Use of Specialized Materials

When it comes to protecting medical instruments against cross-talk, you would require special materials. Here, the shielding process involves placing the metal components in rubber inserts.  Some amount of customization is needed to achieve proper, functional shapes. To choose the ideal metal for your application, you should first find out how much attenuation is necessary for the reduction of radiation strength.   Chemical properties of a material may change when you use it with various types of rubber compounds. And this is the reason why designers need to consider factors like pressure and temperature while selecting EMI shielding materials. Industry-leading suppliers use custom extrusions, rubber strips, sheet stock, and tubing based on particular applications. For medical devices, you may require flag gaskets that help protect medical seals from undesired interference.

The Need for Quality Sealing Materials

High-end medical instruments are expensive, and therefore, shielding suppliers use first-rate sealing or gasket materials to ensure the optimal protection. When monitoring patient heartbeat and blood pressure (BP), medical technicians must use shielded products to protect sensitive medical equipment. It is essential for the correct recording of heart rate and BP.

The Need for Conductive Coatings

When it comes to conductive coatings, they do not take much space when used in electronic devices. If installed professionally, it will help the design engineer to produce the final shielding product without blowing up the budget. Conductive coatings used together with injected-molded plastics in electronic equipment result in superior shielding performance.

Factors to Consider While Designing EMI Shields in Molded Plastic Enclosures

  • The level of shielding necessary to comply with the radiation limits set by the Federal Communications Commission (FCC) to protect equipment from unwanted emissions.
  • Choosing a quality resin, which is well suited to the shielding process used to cover the plastic components with metals.
  • The operational surroundings, which may expose it to a variety of environmental factors such as harsh chemicals, salt fog, extreme temperature conditions, and gases under which the coating is used.
  • Figuring out the range of frequencies that require shielding.
  • The mechanical design of the parts that need EMI protection.

Design Needs to Consider at the Initial Phase

When designing shielding materials, make sure it’s done up front. In fact, the process should be completed in the initial phase of the product design cycle. Ensure that the electronic enclosure, device, and shielding material is designed concurrently to minimize production costs and time to market. Although engineers are knowledgeable about the principles related to Faraday Cage, using the same to design electronic items presents a challenge to them. Device performance in a given environment and compliance to FCC guidelines is essential when assembled systems go through a meticulous EMI testing process in a laboratory. Some of the regulations for conductive coatings can help design engineers to recommend a coating material that complies with the guidelines.

Electric and Magnetic Interference

As far as EMI is concerned, it comes under two main categories, electric and magnetic interference. If you want to attenuate electronic interference, opt for thin conductive coatings of silver or copper for maximum shielding effectiveness. You can choose metal coatings that are one micron thick for those applications having a frequency range of greater than or equal to 30 MHz. Magnetic interference has less than 30 MHz frequency. You should use thicker nickel coverings that ensure optimal shielding efficiency.

Conductive Coatings and Environmental Factors

The ambient setting is also a deciding factor when designing EMI shielding products and conductive coatings. The shielded materials may often have to operate under adverse environmental conditions involving exposure to harsh, corrosive chemicals. They are even exposed to fumes or gases. Besides, they may be used in an outdoor surrounding where salt fog can enter the device. Under these environmental conditions, the corrosion of the shielded items needs to be considered because it affects device performance. Thick nickel plating is ideal for the shielding units to be used in harsh operating environments. It will help to protect the underlying copper coating. And if you are planning to opt for conductive paints, pick nickel instead of copper. Though silver-coated copper paint resists corrosion, it cannot match the resistive properties of nickel in harsh surroundings. Two other options include silver and silver-coated copper paint, but the former is too expensive.

Choose an EMI shielding product supplier with the knowledge and expertise in designing quality fabric shields, gaskets, and electronic enclosures for the medical industry. Opt for shielding solutions that you can personalize based on your application requirements. Make sure that they are budget-friendly and have the potential to offer outstanding shielding effectiveness to protect medical devices and electronics.