What is a perforation

Through holes (VIA), holes in a circuit board that connect wires between layers, transforming the board from a flat structure into a solid one. Single-layer lines are too difficult to cross, double-layer or more lines must be connected through holes. Through the copper on the hole wall, connect the upper and lower circuit copper wire.

What kinds of holes are there

The holes on the circuit board are mainly mechanical holes and laser holes.

1. Mechanical hole

A hole made with a mechanical drill. The internal diameter of the hole is more than 0.2mm. A thicker drill bit will make a larger hole.

Consumer electronics are usually designed with a 0.3mm inner diameter. Ordinary circuit board factories can do 0.3mm mechanical hole.

If the mechanical holes of 0.2mm and 0.25mm are used, the drill bit is thin, slow and easy to break, so the price is more expensive. Not all PCB manufacturers can make such a small mechanical hole.

The drill bit drilled through the circuit board in one fell swish, so the mechanical hole is also called through hole.

2, laser hole

A hole made with a laser. The inner diameter is generally 0.1mm. There are few other specifications for laser holes.

Because the power of laser is limited, it can not directly Pierce the multi-layer PCB board, usually used to do the blind hole on the surface.

The hole diameter of PCB board should be as large as possible: as mentioned above, small drill bit should be used for small hole. Small drill bit has high price and high requirements for board factory. If the board area is larger, even a 0.5mm inner diameter mechanical hole can be used.

Try not to use laser holes: a circuit board with a layer of laser holes is 30% more expensive than a board without laser holes (first-stage board). With 2 laser holes, 30% more expensive than 1 laser hole (second order plate).

Other more expensive designs: The more complex the perforation process, the higher the board price, the cheapest and most expensive dozens of times more. Like 0.2mm mechanical hole than 0.3mm mechanical hole circuit board about 20% expensive; The laminated plate with 2 layers of laser holes overlapping is more than 20% more expensive than the staggered plate with 2 layers of laser holes. The arbitrarily layered interconnect boards that Iphones like to use are more than 10 times more expensive than conventional boards with mechanical holes (all overlapped laser holes).

Intensive drilling, regular or random

Each hole has a finite inner surface area and a finite current.

For power lines, ground lines and other PCB lines that need to pass through high current, need to punch a lot of holes.

These perholes can be arranged in a matrix or randomly. Is there any difference between the two?

The regular ones look better than the random ones. Random arrangement is fast in drawing. Most companies don't require it, and obsessive PCB engineers like to use a regular arrangement.

Matrix type regular arrangement of holes, it is possible to block the signal in some directions stronger, if not deliberately pursue good-looking, random drilling will be more secure.