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Different Material of Circuit Board
The combustibility of a material, also known as flame retardancy, self-extinguishing, flame resistance, flame resistance, fire resistance, flammability and other combustibility, is to assess the ability of the material to resist combustion. The flammable material sample is ignited with a flame that meets the requirements, and the flame is removed after the specified time. The flammability level is...
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A&Q of PCB （2）
9. What is resolution? Answer: Within a distance of 1mm, the resolution of the lines or spacing lines that can be formed by the dry film resist can also be expressed by the absolute size of the lines or spacing. The difference between the dry film and the resist film thickness The thickness of the polyester film is related. The thicker the resist film layer, the lower the resolution. When the ligh...
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PCB SURFACE FINISHING, ADVANTAGES AND DISADVANTAGES
Anyone involved within the printed circuit board (PCB) industry understand that PCBs have copper finishes on their surface. If they are left unprotected then the copper will oxidize and deteriorate, making the circuit board unusable. The surface finish forms a critical interface between the component and the PCB. The finish has two essential functions, to protect the exposed copper circuitry and t...
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A&Q of PCB, Why solder mask plug hole?
1. Why is the BGA located in the solder mask hole? What is the reception standard? Re: First of all, the solder mask plug hole is to protect the service life of the via, because the hole required for the BGA position is generally smaller, between 0.2 and 0.35mm. Some syrup is not easy to be dried or evaporated, and it is easy to leave residues. If the solder mask does not plug the hole or the plug...
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Half-hole Design of Circuit Board
The metalized half-hole means that after drill hole (drill, gong groove), then the 2nd drilled and shaped, and finally half of the metalized hole (groove) is retained. In order to control the production of metal half-hole boards, circuit board manufacturers usually take some measures due to process problems at the intersection of metallized half-holes and non-metallized holes. Metallized half-hole...
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Why most multi-layer circuit boards are even-numbered layers?
There are single-sided, double-sided and multi-layer circuit boards. The number of multi-layer boards is not limited. There are currently more than 100-layer PCBs. The common multi-layer PCBs are four layer and six layer boards. Then why do people have the question "Why are PCB multilayer boards all even-numbered layers? Relatively speaking, even-numbered PCBs do have more than odd-numbered PCBs, ...
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Why printed circuit board need impedance control?
Why printed circuit board need impedance control? In the transmission signal line of an electronic device, the resistance encountered when the high-frequency signal or electromagnetic wave propagates is called impedance. Why do PCB boards have to be impedance during the manufacturing process of the circuit board factory? Let us analyze from the following 4 reasons: 1. The PCB circuit board of the ...
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How to control circuit board warpage&twist
Warping of the battery circuit board will cause inaccurate positioning of the components; when the board is bent in SMT, THT, the component pins will be irregular, which will bring a lot of difficulties to the assembly and installation work. IPC-6012, SMB-SMT Printed circuit boards have a maximum warpage or twist of 0.75%, and other boards generally do not exceed 1.5%; the allowable warpage (doubl...
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Grid copper, solid copper. Which one?
What is copper coating? The so-called copper pour is to use the unused space on the PCB as a reference surface and then fill it with solid copper. These copper areas are also called copper filling. The significance of copper coating is to reduce the impedance of the ground wire and improve the anti-interference ability; reduce the voltage drop and improve the efficiency of the power supply; if it ...
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PCB Pad size
When designing PCB pads in PCB board design, it is necessary to design strictly in accordance with relevant requirements and standards. Because in the SMT patch processing, the design of the PCB pad is very important. The design of the pad will directly affect the solderability, stability and heat transfer of the components. It is related to the quality of the patch processing. Then what is the PC...
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