In manufacturing P.C.B one important step is to making via hole on P.C.B. for placing the required components in double side and multilayer P.C.B. There are two types of hole on P.C.B which are different from each other in size and their job nature.
- Large hole
These kind of holes on P.C.B used to installed different electronics equipment like Diode, Capacitor, Transistor, Resistor) according to the requirement of the circuit for which is P.C.B are made.
- Via holes (small hole)
A small pad hole’s which is used to combine the different track path in double side or multilayer P.C.B is called via holes. They are not meant for holding components. Electrical current flow from these via hole from one side layer of P.C.B to other sides of P.C.B. Due to this procedure less place (space) is used on P.C.B for wiring & component interconnection routing. After drilling the holes, via hole go through electroplating process. One other method that is used in P.C.B is non P.T.H (Plated through Holes) in which revert of copper are used in via holes.
There are three types of via holes are used in P.C.B manufacturing:
- Plated through via holes
These types of via holes are commonly used in double sided and multi-layer P.C.B. These via holes make through all layers of P.C.B and these via holes are visible on both outer surfaces of P.C.B. Due to this process current flow from outer one side to other side of P.C.B which covers all layers of a multi-layer P.C.B.
- Blind via holes
These via holes connect the outer surface to the next or few near lawyers of P.C.B. In this process a complete hole does not make through from all layers of P.C.B. Since they have dead end in P.C.B that is why they are called blind via holes. These type of via holes are used to connect surface traces to inner layers of PCB.
- Buried via hole
These via holes are also used in multi-layer P.C.B. These via holes connect inner layers of P.C.B but they are not visible on outer surfaces of the P.C.B. Current flow between inner layers trough these via holes.