Everyone knows that there are various holes on the circuit board, and2Above the layer, conduction is achieved through copper holes. Today, we will analyze the difference between plated holes and conductive holes in flexible circuit boards:

 

Usually on circuit boardsPTHHoles have two purposes, one is for welding traditional materialsDIPThe holes used for the part feet must have a diameter slightly larger than the welding foot diameter of the part in order to insert the part into the holes for welding.

 

conventionalvia(Conductive hole)Another smaller onePTHIt is commonly referred to asvia(Conductive hole), is used to connect and conduct circuit boards(PCB)The copper foil circuit between two or more layers is used becausePCBIt is formed by stacking and accumulating many layers of copper foil, with each layer of copper foil(copper)There will be an additional layer of insulation between them, which means that the copper foil layers cannot communicate with each other. The connection of their signals relies onviaThat's why Chinese calls it“Conductive hole”.

 

Blind-Via-HoleThe left image is a side sectional view of the circuit board, which can be imagined as an ant colony inside a glass bottle. This is a piece of copper foil with six layersPCBWe can take this piecePCBImagine a building with six floors, where each copper foil layer represents a floorvia(Conductive hole)It's like a staircase connecting floors, and there can be several staircases in this building, but not every one of them may connect to all floors. It may only connect the third and fourth floors, and nothing else. This kind of hole(via)We call it【Buried Via Hole(Buried hole)】Because there are no visible holes from the outside. becauseviaThe purpose is to conduct different layers of copper foil, which requires electroplating to conduct, soviaThat's rightPTHOne of them.

 

Green paint coveragevia(Conductive hole)But nowviaMost of them will use green paint(solder mask)Covering it up, just like the left picture, especially the phone board, because the parts on the board are denser and denser, someViaIt may even be placed directly below the parts to prevent them from interfering with each otherviaAccidentally short circuiting can cause quality issues, so most of them are covered with green paintvia.

 

Because someviaThere will be printed solder paste on top, and the board will flow through the reflow oven(reflow)At that time, solder paste is very likely toviaIt flows to the other side of the board and causes a short circuit problem, so the currentPCBMost crafts willviaMake the aperture small and cover it with green paint to avoid potential quality issues in the future.

 

Of course, many people believe that using green paint to cover conductive holes may pose quality risks, as there may be risks of incomplete hole covering or corrosion caused by chemical residue. However, it cannot be denied that using green paint to cover holes is currently the cheapest and most acceptable filling method.

 

In addition to using green paint to cover the holes, some people also use resin to fill the holes first and then cover them with green paint. This method is more in line with quality requirements, but with an additional process, the cost naturally increases. Additionally, if it is a solder pad/For through holes or blind holes on solder pads, we usually require the use of copper plug holes, followed by surface treatment(Finished)To avoid the risk of solder paste flowing into the through-hole.

【 Reading Tips and Disclaimer 】

【 Reading Tips 】

The above is the accumulation of some experience in our company. Due to the wide range of process issues, it is not comprehensive and only analyzes common problems. With the development of the electronics industry

New updates and technological issues continue to emerge. Since its establishment, our company has been constantly pursuing product innovation, keeping pace with the times, familiar with various complex production processes, and able to provide comprehensive assistance to various customers.

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