Through-hole technology of circuit board proofing

Vias are one of the important components of multilayer printed circuit boards. The cost of drilling usually accounts for only 30% to 40% of the proofing cost of printed circuit boards. From this point of view, it is divided into two parts: a small part as the electrical connection between the layers; The other part is used as a fixing device. Judging from the proofing process of printed circuit boards, there are three kinds of through holes: blind holes, buried holes and through holes.
A through hole refers to a hole that passes through the whole circuit board, and can be used to realize internal interconnection, and can also be used as a mounting and positioning hole for components. Because through-holes are easy to realize and low in cost, most printed circuit boards adopt through-holes instead of the other two.
On the upper and lower surface layers of pcb, the blind holes have corresponding depths. Used to connect the surface circuit and the inner circuit. The depth of the hole usually does not exceed a certain ratio (aperture).
Buried holes refer to the connected holes in the inner layer of pcb, which do not extend to the surface of pcb. The above two types of holes are located inside the PCB. Through-hole molding is adopted before pressing, and there may be multiple inner layers overlapping during the through-hole molding process.
And the application of blind holes and buried holes can greatly reduce the size and quality of HDI (high density interconnection) PCB, reduce the number of layers, improve the electromagnetic compatibility, increase the characteristics of electronic products, reduce the cost and make the design easier and faster. For more consultation on circuit board proofing process, please contact customer service