In order to meet the requirements of customers, the through hole of circuit board must be plugged. After a lot of practice, the traditional aluminum sheet plug hole technology is changed, and the solder mask and plug hole on the circuit board surface are completed with continuous plug and printing. Stable production and reliable quality.
Via hole plays an important role in the interconnection of circuits. The development of electronic industry also promotes the development of PCB, and puts forward higher requirements for PCB manufacturing process and surface mounting technology. The via hole plug technology came into being and should meet the following requirements:
a. The copper in the via hole is enough, and the solder mask can be plugged or not;
b. There must be tin and lead in the via hole, with certain thickness requirements (4 μ m), and no solder resist ink is allowed to enter the hole, resulting in tin beads hidden in the hole;
c. Via hole must have solder resist ink plug hole, opaque, no tin ring, solder bead and leveling requirements.
With the development of electronic products in the direction of “light, thin, short and small”, PCB also develops to high density and high difficulty. Therefore, there are a large number of SMT and BGA PCBs. Customers require plug holes when mounting components, which have five main functions:
a. In order to prevent the short circuit caused by tin passing through the component surface through the via hole during the wave soldering of PCB, especially when we put the via hole on the BGA pad, we must first make the plug hole and then gilt it to facilitate the BGA welding.
b. Avoid flux residue in the via hole;
c. After the surface mounting and component assembly of the electronic factory are completed, the PCB must absorb vacuum to form negative pressure on the testing machine;
d. Prevent solder paste from flowing into the hole to cause false soldering and affect mounting;
e. To prevent solder bead from popping out during wave soldering, resulting in short circuit.Types of via hole and plug hole:
- Soldermask plug hole
- Resin plug hole(vippo)