How to effectively troubleshoot electromagnetic interference(EMI) issues?
How to effectively troubleshoot electromagnetic interference(EMI) issues?
Electronics, telecommunications equipment, and industrial control devices are all designed with the ultimate goal of achieving high reliability, efficiency and performance. In response to these requirements, electric circuit design has become more complicated. Due to the trend in product miniaturization, the available internal space for circuit boards is increasingly minimized. As a result, chip components are compacted in limited space which then leads to negative impacts of electromagnetic interference. How to manufacture products that comply with EMI compatibility regulations while maintaining stability, multi-function, and high efficiency has become an imperative topic in product development.
Common EMI shielding designs are as follows:
*Chassis Shielding:
The use of metal enclosure has the best EMI shielding effect. There are currently a variety of metal or metal-like options on the market, but they are relatively heavier and more costly with a limited casing variety. Another option is to use aluminum-magnesium alloy material, which has the advantages of product aesthetics and lighter weights. The disadvantage is that the die-casting process of the enclosure may cause cracks and holes in the material, and the surface treatment process could produce toxic waste.
Another option is to use plastics as the main material while supplemented by metal-processed shielding designs. This method has both light weight and cost advantages, and thus has become a mainstream application for many electronics and mobile phones. Common designs are to use plastics coating with conductive metals or blending with conductive materials such as metal powder, metal sheet, metal fiber or conductive carbon fiber to reduce surface resistance inside the plastic casing. However, this method requires top-notch technical expertise to address complex challenges such as coating uniformity and short circuits that might affect shielding effectiveness.
*Internal Shielding
This method works by metallizing the interiors of plastics to prevent or reduce EMI. Commonly used methods include metal evaporation and metal plating or coating which both involve metallizing component surface inside plastic enclosure. The challenge is that the thermal expansion coefficients of metal and plastic are different. The inner metal film might also peel due to increased temperatures. When internal metal coating is scratched on assembly lines, shielding effectiveness could be compromised.
*In summary, the use of partial shielding to solve the EMI problem is a direct, fast, efficient and the most cost-effective way. Such EMI shielding refers to the use of conductive or magnetic conductive metal shields to directly cover high-frequency electronic components that are susceptible to EMI to reduce negative impacts of electromagnetic interference and thereby enhance the component's immunity to disturbance. This shielding method can block interference sources from the outside or reduce the radiation interference to a controllable range. Designers must first detect the EMI source, distance, and intensity when electronics are unshielded, and then determine the most appropriate shielding quantity, features and materials.
For partial shielding needs, OSCAR PRECISION offers many EMI shielding shrapnel models for your choice, including various metal materials, measurements and shapes. We can also customize metal coatings of PCB spring contacts based on customer requirements. Our self-developed CCD detector can be used for comprehensive inspection of metal spring contacts to ensure the consistency and stability of products. We welcome requests for a small quantity of samples for preliminary testing. If you have any questions or requirements, please feel free to contact us at sales@oscarprecision.com.
