PCB News - How much do you know about the classification of PCB shielding covers

Circuit board factory: How much do you know about the classification of PCB shielding covers~

Circuit board factory: We can see shielding covers on many PCBs, especially in consumer electronic products such as mobile phones. The PCB of the mobile phone is covered with shielding covers. The shielding cover mainly exists in the PCB of the mobile phone. This is mainly because the mobile phone has various wireless communication circuits, such as GPS, BT, WiFi, 2G/3G/4G/5G, some sensitive analog circuits and DC-DC switching power supply circuits usually need to be used The shield cover is isolated. On the one hand, they do not affect other circuits, on the other hand, they prevent other circuits from affecting themselves.

This is one of the functions of preventing electromagnetic interference; another function of the shielding cover is to prevent collisions. PCB SMT will be divided into multiple boards. Usually, adjacent plates need to be separated to prevent close collisions during subsequent testing or other transportation.

The raw materials of the shielding cover generally include nickel silver, stainless steel, tinplate, etc. At present, most of the shielding covers are made of nickel silver.

The characteristic of nickel silver is that the shielding effect is slightly worse, it is softer, the price is more expensive than stainless steel, and it is easy to tin; the shielding effect of stainless steel is good, the strength is high, and the price is moderate; but it is difficult to tin (it is almost impossible to tin without surface treatment. Improved after nickel plating, but it is still not conducive to the patch); tinplate has the worst shielding effect, but the tinplate is good and the price is cheap.

The shield can be divided into fixed type and detachable type.

The one-piece shielding cover fixed type is generally called a single-piece type, which is directly attached to the PCB by SMT, and is generally called Shielding Frame in English.

The detachable two-piece shielding cover is generally called the two-piece type. The two-piece shielding cover can be opened directly without the help of a hot air gun tool. The price is more expensive than the single-piece type. The bottom SMT is soldered on the PCB and is called the Shielding Frame, and the top is called the Shielding Cover. It is directly buckled on the Shielding Frame for easy disassembly. Generally, the lower frame is called the shielding frame, and the upper cover is called the shielding frame. It is called a shield. Frame recommends using nickel silver, which is good for tinning; Cover can use tinplate, which is mainly cheap. The two-piece type can be used in the initial stage of the project to facilitate debugging. After the hardware debugging is stable, consider using the single-piece type to reduce costs.

There is still more professional knowledge to learn about the shielding cover. Many new beginners will always suffer from the loss of the shielding cover when doing PCB-related projects. This article summarizes some relevant experiences for you, I hope Can help you.