First of all, the PCB we hold in our hands can usually be seen as a single-layer or multi-layer board. In double-sided and multi-layer boards, in order to connect the printed wires between the layers, the wires need to be connected in each layer. Open a common hole at the intersection of the, but pay attention to the outer diameter of the hole and the size of the drilled hole, so we call it a through hole, also called a metalized hole. The via processing methods are divided into three types: via hole opening, via hole cover oil and via hole plug oil. Next, the editor will talk to you about the definition of hole plug oil. Through hole plugging oil is to guide the hole of the through hole to be plugged with ink, and the emphasis is on the quality and compactness of the plug hole. The inspection standard for the treatment of via plug oil is to be opaque, and it must be covered and blocked by ink. The second is that the orifice should not be yellowed, and it should not be stained with tin. The via plug oil process is an important supplement to the via plug oil. Generally, high-quality PCB boards are required to be made into via plug oil. The via plugging oil first fills the via hole with ink. After the plug hole, the via hole cannot be blocked by light, so that the ink on the solder mask will not flow into the via hole, so as to achieve no yellowing of the via hole. effect. The smaller the vias are, the easier it is to plug them. The fortress oil vias are not easy to be too large, the maximum is 0.5mm, so it is recommended to cover oil for holes larger than 0.5mm. The vias mentioned above are usually used for interlayer conduction. Therefore, in order to avoid short circuits during use of the board, cover oil is usually used to ensure electrical performance and avoid the risk of short circuit with other components during use. Therefore, if some PCBs need vias as test points or heat dissipation, It will open the window. The above is the understanding of PCB via plugging oil summarized by the PCB editor. I hope to help you. PCB always insists on using superb technical force, sophisticated production equipment, perfect testing methods, and product quality higher than industry standards. The warm and thoughtful service has won praise and welcome from merchants and users all over the world.