Why do PCB board making holes need to be plugged? Conductive holes are also known as via holes. In order to meet customer requirements, the circuit board via holes must be plugged. After a lot of practice, the traditional aluminum plug hole process is changed, and the circuit board surface solder mask and plug hole are completed with white mesh. Stable production and reliable quality.
Via hole plays the role of interconnection and conduction of lines. The development of the electronics industry also promotes the development of PCB, and also puts forward higher requirements on PCB manufacturing technology and SMT processing technology. Via hole plugging technology came into being, and should meet the following requirements at the same time:
1. There is copper in the via hole, and the solder mask can be plugged or not plugged;
2. There must be tin-lead in the via hole, with a certain thickness requirement (4 microns), and no solder mask ink should enter the hole, causing tin beads to be hidden in the hole;
3. The through holes must have solder mask ink plug holes, opaque, and must not have tin rings, tin beads, and flatness requirements.
With the development of electronic products in the direction of "light, thin, short and small", PCBs have also developed to high density and high difficulty. Therefore, a large number of SMT and BGA PCBs have appeared, and customers require plug holes when mounting components, mainly including Five functions:
1. Prevent the tin from passing through the via hole to the component surface and cause a short circuit when the PCB is wave soldered; especially when we put the via hole on the BGA pad, we must first plug the hole and then plate it with gold to facilitate the BGA soldering.
2. Avoid flux residue in the vias;
3. After the SMT processing and component assembly in the electronics factory are completed, the PCB must be vacuumed to form a negative pressure on the testing machine to complete:
4. Prevent surface solder paste from flowing into the hole, causing false soldering and affecting placement;
5. Prevent the tin balls from popping up during wave soldering, causing short circuits.