Ultrasonic Spray Coating Electromagnetic Shielding Layer

In the current era of highly integrated electronic devices, electromagnetic signal interference has become a key factor restricting device performance. Ultrasonic spraying machine, as a precision coating equipment, forms a uniform electromagnetic shielding layer on the surface of electronic components through a unique atomization principle, providing an efficient solution to this problem.

The core of this technology is to use high-frequency vibration to atomize conductive ink into micrometer sized particles. When the ultrasonic generator generates high-frequency vibrations above 20kHz, energy is transmitted to the nozzle through the transducer, causing the ink to split into uniform droplets under resonance. This atomization method avoids the turbulence phenomenon of traditional high-pressure spraying, allowing droplets to uniformly adhere to the substrate surface at a controllable speed, laying the foundation for the subsequent formation of a continuous shielding film.

Silver or copper based conductive inks used for preparing shielding layers retain the high conductivity of metals while possessing fluid properties. Silver based ink has better conductivity and a volume resistivity as low as 10 Ω· m, making it suitable for scenarios that require extremely high shielding effectiveness; Copper based ink has a cost advantage, as it can maintain stable performance in high humidity environments after surface antioxidant treatment. Both types of ink need to meet specific viscosity parameters, typically within the range of 100-500cP, to match the atomization requirements of ultrasonic spraying.

During the manufacturing process, ink is transported to the nozzle through a precision feeding system, atomized by ultrasonic waves, and uniformly covered on the surface of substrates such as PCB boards and chip packaging along with the carrier gas. By controlling the nozzle movement speed (usually 0.5-5mm/min), spraying distance (10-30mm), and atomization frequency, the thickness of the shielding film can be accurately controlled within 1-5 μ m. This ultra-thin feature not only meets shielding requirements but also does not increase device volume, perfectly adapting to the current trend of miniaturization in electronic devices.

The formed EMI shielding film works through two mechanisms: one is to use the continuity of metal particles to form a conductive network and reflect electromagnetic energy back; The second is to absorb some electromagnetic energy through the metal components in the ink and convert it into thermal energy for dissipation. Test data shows that a silver based shielding film with a thickness of 3 μ m can achieve a shielding efficiency of over 60dB in the 1-10 GHz frequency band, which is sufficient to block the interference signals generated by the vast majority of electronic devices.

This technology is widely used in the field of consumer electronics, such as motherboard shielding for smartphones and sensor protection for smartwatches. In the field of medical electronics, it can provide a stable electromagnetic environment for precision monitoring equipment, ensuring accurate detection data. In the aerospace field, lightweight ultra-thin shielding layers can reduce equipment load while resisting interference from complex electromagnetic environments.

Compared to traditional vapor deposition or sputtering processes, ultrasonic spraying has significant advantages: the material utilization rate can reach over 85%, far exceeding the 40% of traditional spraying; Non contact coating avoids damage to precision components; A single device can achieve rapid switching of multiple types of ink, adapting to flexible production needs. With the development of 5G communication and IoT technology, the requirements for electromagnetic compatibility are constantly increasing. This coating technology, which combines precision and economy, is expected to play a key role in more high-end manufacturing fields.

About Cheersonic

Cheersonic is the leading developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings to protect, strengthen or smooth surfaces on parts and components for the microelectronics/electronics, alternative energy, medical and industrial markets, including specialized glass applications in construction and automotive.

Our coating solutions are environmentally-friendly, efficient and highly reliable, and enable dramatic reductions in overspray, savings in raw material, water and energy usage and provide improved process repeatability, transfer efficiency, high uniformity and reduced emissions.

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