With the development of the electronics industry, promoting the development of PCB circuit boards, it also puts forward higher requirements on the production process and surface mount technology of printed circuit boards. Hole plugging technology came into being. PCB circuit board plugging holes are usually after the solder mask layer, and then a second layer of ink is used to fill the heat dissipation holes with a diameter of 0.55mm or less. Why do PCB circuit boards need plugging holes?
1. Prevent surface solder paste from flowing into the hole, causing false soldering and affecting placement.
2. The PCB circuit board plug hole can avoid the flux residue in the via hole, and can maintain the surface flatness;
3. When there is a via hole on the BGA pad, it must be plugged first, and then gold-plated to facilitate the soldering of the BGA;
4. The plugging process can prevent the tin from penetrating the via hole and causing short circuit when the PCB circuit board is wave soldered, and prevents the tin bead from popping up during the wave soldering, causing the PCB circuit board to short circuit;
PCB circuit board plugging technology can be described as diverse, the process flow is particularly long, the process is difficult to control. At present, the common plug hole technology includes resin plug hole and electroplating hole filling. The resin plug hole is filled with epoxy resin after copper plating on the wall of the via hole, and finally copper plating on the resin surface, the effect is that the hole can be connected. And there are no dents on the surface, which does not affect welding. Electroplating hole filling is to directly fill the via hole through electroplating, there is no gap, and it is good for welding, but the process capability is very demanding.
