Pay (VIA), the holes on the circuit board, connect the circuit between different layers, and change the circuit board from the plane structure to a three -dimensional structure.
The single -layer line is too difficult to cross the cross. Double or more layer lines must be connected by over -hole. The copper on the hole wall is connected to the upper and lower circuit copper wires.
Single -layer PCB, sometimes unable to wir
Large and small excessive holes, connecting circuits at different levels
There are two types of holes on the circuit board: mechanical holes and laser holes.
1. Mechanical hole
A hole drilling with a mechanical drill. The internal diameter of the hole is above 0.2mm. The holes drilling with a thicker drill will be greater.
Consumer electronics is usually designed according to the 0.3mm internal diameter. Ordinary circuit board factories can make 0.3mm mechanical holes.
If you use a mechanical hole of 0.2mm and 0.25mm, the drill bit is easy to break the drill speed slow drilling speed, and the price will be more expensive. Not all PCB manufacturers can make such a small mechanical hole.
The drill head drilled the circuit board at once, so the mechanical hole was also called the hole.
2. Laser hole
Pole with laser. The inner diameter is generally 0.1mm. There are few other specifications of laser holes.
Because the power of the laser is limited, it cannot directly penetrate the multi -layer PCB board, which is usually used as a blind hole on the surface layer.
The precautions of PCB plate over -hole design are as large as possible:As mentioned above, the small hole should be used with small drills. The price of small drills is high, and the requirements for board factories are also high. If the circuit board is large, it can even use a mechanical hole with a diameter of 0.5mm.
Try not to use laser holes:A circuit board with a laser hole is 30%(one -step) than a laser holes without laser holes. With 2 layers of laser holes, 30%(two -step) is more expensive than 1 layer of laser holes.
Other more expensive designs:The more complicated the hole process, the higher the price of the circuit board, the cheapest and the most expensive differences of more than dozens of times. Like 0.2mm mechanical holes than 0.3mm mechanical holes circuit boards are about 20%expensive; 2 layers of laser holes overlap the overlapping holes, more than 20%more expensive than the two -layer laser holes; Apple mobile phones like any layer interconnection The board of the board is more than 10 times more expensive than ordinary mechanical holes (the entire board is overlapping laser holes).
The area of the inner surface of each perforated is limited, and the current current is limited.
For PCB lines such as power cords and ground wires, a lot of holes are required through large current PCB lines.
Random punch and rules
These holes can be arranged by matrix rules or random arrangements. Is there any difference between these two?
Rules are arranged better than random arrangement. Randomly arranged drawing speed. Most companies do not have compulsory requirements. PCB engineers who have "obsessive -compulsive disorder" like to arrange them with rules.
The excessive holes arranged in the matrix rules may be stronger in some directions. If you do not deliberately pursue good -looking, random punching will be more secure.