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Do you know why pcb is green?

Have you noticed the color of the circuit board? Many people may be asking: Why are PCBs green? Actually, the circuit board colors we see are the colors of solder resist. The solder resist can prevent the occurrence of wrong soldering of the components, delay the service life of the device, and prevent the oxidation and corrosion of the device circuit. If you have a better understanding of electronic products, you will find that the PCB color is generally green. So why pcb is green?

green pcb

This is mainly because the green solder mask process is the most mature and simple, and the green pcb board is also more environmentally friendly. In addition to green, circuit board colors have white, yellow, red, blue, matte colors, and even chrysanthemum, purple, black, bright green, etc. White exists because that we must use it to make lamps and lanterns. And the use of other pcb colours is primarily to distinguish different product samples. In the entire stage of the company, from R&D to product landing, depending on the various uses of the PCB. The experiment pcb board color may be purple, the key pcb color will be red, and the internal pcb color of the computer will be black. So they are marked by color. As for the green pcb board, its solder mask ink is the oldest, cheapest, and most popular. So it’s not difficult to understand why pcb is green.

There are several reasons explain why pcb is green:

1. In PCB processing, the production of electronic products includes board making and post filming. During the process, there are several processes to go through the yellow light room, and the green PCB board has the best visual effect in the yellow light room;

 2. Secondly, during SMT patch processing, the steps of tinning, patching and AOI calibration all require optical positioning calibration. And the green circuit board is more friendly when it is recognized by the instrument;

 3. Part of the inspection process relies on worker observation (but now most of them use flying probe testing instead of labor), staring at the board under strong light, green pcb board is friendly to eyes;

 4. Green PCBs are relatively environmentally friendly. And no toxic gas will be released when the waste boards are recycled at high temperature. Other PCB colors, such as blue and black, are doped with cobalt and carbon, respectively, because they have weak electrical conductivity, and there is a risk of short circuit. In addition, like black, purple, and blue lights, the circuit board colors is too dark, which will increase the difficulty of the inspection and maintenance of the motherboard, and the process is not easy to control.

green solder mask pcb

 Taking the black board as an example, the black board is most prone to problems in the production process and the ratio of raw materials. A little carelessness will cause obvious color difference and lead to a high PCB defect rate. The traces of the black circuit board are not easy to distinguish, which will increase the difficulty of post-maintenance and debugging. Many PCB factories do not use black PCB very much. Even in the fields of military industry and industrial control, products with extremely high-quality requirements are mainly made of green PCB substrates. The circuit board colors do not affect its performance in the slightest. In summary, it is not difficult for us to understand why pcb is green.