On Bosch Precision Metalshield canThe importance of shielding EMI

EMIDefinition of

EMI can be defined as the electromagnetic wave energy that affects the functionality of electronic devices. The source of EMI may sometimes be naturally occurring environmental events, such as electric storms and solar radiation; But usually, the EMI source is another type of electronic device or electrical system. Although EMI can be generated from any electronic device, certain devices and components (such as mobile phones, welding machines, motors, and LED screens) are more prone to interference than others.

Due to the limited independent operation of electronic products, they are typically designed to operate in the presence of a certain amount of EMI, which is particularly important in military grade and aviation electronic equipment, as well as equipment that requires high reliability in all situations.

Briefly describeshield canThe Importance of Shielding EMI

1. The commercial necessity of blocking

A project needs to consider blocking issues during the planning phase, so that the cost of blocking measures can be minimized.

If we wait until the problem is exposed to investigate and make up for it, it often requires a considerable cost.

Shielding measures often result in increased costs and instrument weight. If other EMC methods can be used to address this issue, shielding should be minimized as much as possible.(The implication is that blocking is the last resort)

For PCB, the following two points should be noted:

1. Bring the wires and components as close as possible to a large metal plate (this metal plate does not refer to the shielding body)

2. By placing electrical components and circuits as close as possible to the ground (reducing electromagnetic interference between layers and allowing the ground to absorb some interference), even if shielding is required, the demand for shielding effectiveness (SE shielding effectiveness) can be reduced.

2. The concept of shielding

Shielding is equivalent to a filter placed on the propagation path of electromagnetic waves, forming high impedance for a portion of the frequency band.The larger the impedance ratio, the better the shielding effectiveness.

For general metals, a thickness of 0.5mm can provide good shielding effect for electromagnetic waves at 1MHz, and very good shielding effect for 100MHz. The problem is that thin metal shielding is not effective for frequencies below 1MHz or pores. This article focuses on this aspect.

3. A larger spacing and rectangular shielding would be better

(1) Greater spacing between circuits and shields can reduce mutual interference;

(2) A rectangular (or irregular) shielding shape can minimize frequency resonance as much as possible;Square shells often cause resonance;

But overall, circuit boards are usually located inside shielding bodies, and their components, circuits, etc. will change the expected resonance frequency point, so there is no need to worry too much.

Dongguan Bosi Hardware, as a leader in the customized EMI shielding cover processing industry, has been dedicated to researching shielding cover technology for 20 years. It has introduced German CNC micro sampling machines, automatic sampling systems, and fully computer-controlled processesQuick and accurate province,threeTian Da sample province mold making,12Urgent sample production within hours,High repeatability accuracy0.01mm，Flatness can reach0.02mm，Pioneering the industry with strong capabilitiesSolving the pain points and difficulties of customized precision hardware non-standard parts for customers, BosiEMI shielding cover has good shielding effect and high precision, making it the first choice for customers to purchase!

Contact: Manager Wang(24-hour consultation hotline)