Do you know the common through-holes, blind vias and buried vias in circuit board customization?

Circuit board customization manufacturers take you to understand the common through holes, blind holes and buried holes of circuit boards

In our printed circuit boards (PCB), there are three common types of drilling: through holes, blind holes and buried holes.

Through holes (through holes) are used to connect copper foil circuits between conductive patterns in different layers of the circuit board, but they cannot be inserted into the lead pins of components or other materials in the copper-plated holes of reinforcing parts. A printed circuit board (PCB) is formed by stacking many layers of copper foil. The reason why the copper foil layers cannot communicate is that each layer of copper foil is covered with an insulating layer, so they need to rely on through holes for signal links between them, so they must have a Chinese name to pass.

The customized through holes of the circuit board must pass through the plug holes to meet the needs of customers. In changing the traditional aluminum plate plugging process, the welding resistance and plugging on the surface of the circuit board are completed by using a white mesh, which makes the production more stable, the quality more reliable, and the application more perfect. With the rapid development of the electronics industry, there are higher requirements for printed circuit board (PCB) manufacturing technology and surface mounting technology. At the same time, the following requirements need to be met:

1. Only copper is needed in the hole, and the welding resistance can not be inserted;

2. There must be a certain thickness (4um) of tin-lead in the hole to prevent solder mask ink from entering the hole and causing tin beads to enter the hole;

3. The through hole must be provided with opaque, solder mask ink plug holes without tin rings and beads, and must be flat.

Blind holes are used to connect the outermost circuit with the plated holes between adjacent inner layers of a printed circuit board (PCB). Since the opposite side cannot be seen, it is called a blind hole. In order to increase the space utilization between the board and the circuit layer, blind vias are used. Blind holes are through holes that lead to the surface of the printed circuit board.

The blind holes are located on the upper and lower surfaces of the circuit board and have a certain depth. Used for the connection between the surface circuit and the bottom internal circuit. Generally, the depth of the hole has a specified ratio (pore size). Special attention should be paid to this production method, and the drilling depth must be just right, otherwise it will cause difficulties in electroplating in the hole. As a result, few factories will adopt this production method. In fact, you can also drill holes on the circuit board layers that need to be connected in advance, and then glue them together. However, accurate positioning and alignment devices are required.

Buried vias refer to the connections between any circuit layers inside the printed circuit board (PCB), but are not connected to the outer layers, which means that there is no through hole extending to the surface of the PCB.

After bonding the circuit board, the production process cannot be completed by drilling. It is necessary to drill holes in each circuit layer. First, the inner layer is partially bonded, then electroplated, and finally all bonded. Because the operation process is more difficult than the original through holes and blind holes, the price is also the most expensive. This manufacturing process is usually only used for high-density circuit boards to increase the space utilization of other circuit layers

In the production process of printed circuit boards (PCB), drilling is very important. The simple understanding of drilling is to drill the required through holes on the copper clad board, the through holes have the function of providing electrical connections and fixing devices. If the operation is not correct and causes problems during the through-hole process,

The device cannot be fixed on the circuit board, which will affect the use of light on the circuit board, and the entire circuit board will be scrapped. The drilling process is very important.