Why are PCB boards mostly green?

- Sep 18, 2020-

I don't know if you have found such a situation, most of the PCB boards are green, while other color circuit boards are relatively rare. Why is this? Others say that black PCB boards represent high-end, is this really the case?

First of all, let's get to know this green board first. Printed circuit board (PCB) usually consists of pads, vias, solder mask, silk screen, copper wires, various components and other parts. Among them, the solder mask (solder mask) refers to the part of the printed circuit board to be painted green. In fact, solder mask ink is not only green, but also red, yellow, blue, purple, black, etc., but green is the most common.

The role of solder mask:

(1) Prevent physical disconnection of conductor circuits;

(2) Prevent short circuit caused by bridging during welding process;

(3) Only solder the parts that must be soldered to avoid waste of solder;

(4) Reduce copper pollution to the soldering trough;

(5) Prevent insulation deterioration and corrosion caused by external environmental factors such as dust and moisture;

(6) With high insulation, it is possible to increase the density of the circuit.

Why are most PCB boards green? The main reasons are as follows:

1. Green has little irritation to eyes. Since childhood, the teacher told us that green is good for eyes, protects eyes and resists fatigue. The production and maintenance personnel are not prone to eye fatigue when staring at the PCB board for a long time, and the eyes are less harmful.

2. Lower cost. Since green is the mainstream in the production process, the purchase of natural green paint will be larger, and the purchase cost of green paint will be lower than other colors. At the same time, using the same color paint in mass production can also reduce the replacement cost.

3. When the board is soldered in SMT, it has to go through tinning, post filming and final AOI verification. These processes all need to be optically positioned and calibrated. The green background color is better for the recognition of the instrument.

Black PCB board is more high-end?

Since about 2007, everyone began to pay attention to the color of PCB boards. This is mainly because the high-end versions of major manufacturers such as FASTPCBA and Jingbang have adopted black PCB color design, so people gradually think that black PCB boards are It must be high-end. But in fact, this perception is not correct. The difference between black PCB and other color PCBs such as green PCB, blue PCB and yellow PCB lies in the color of the solder mask applied at the end. If the PCB design and manufacturing process are exactly the same, the color will not have any effect on performance, nor will it have any effect on heat dissipation.

Green circuit board

Regarding the black PCB, since the traces on the surface are almost completely covered, it causes great difficulty in later maintenance. Therefore, it is a color that is not convenient to manufacture and use, and the black PCB is the most difficult for holes, so the yield rate Relatively speaking, it is lower than other color PCB boards, so the price of black is relatively more expensive.

Black circuit board

The reason why "color represents high-end or low-end" is because manufacturers like to use black PCBs to make high-end products to demonstrate the stability and advancement of the process, and use red, blue, green, and yellow to make low-end products. The summary is: the product gives the color meaning, not the color gives the product meaning. Regardless of whether it is a black PCB board or a green PCB board, good performance is a good board.

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