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The color on the surface of the PCB boards is actually the color of the solder mask. The solder mask can prevent the occurrence of component mis-soldering and delay the service life of the device by preventing the oxidation and corrosion of device circuits. If you are familiar with electronic products, you will find that the color of PCB boards is generally green. This is mainly because the green solder mask process is the most mature and simple, and green boards are also more environmentally friendly. In addition to green, PCB boards are also available in white, yellow, red, blue, matte, and even orange, purple, black, bright green and other colors. The presence of white is because it is a pigment that must be used for the production of lamp products, and the use of other colors is mostly for distinguishing different product samples. During the entire phase from research and development to product implementation, the experiment board may use purple, the key board may be red, and the boards inside the computer may be black, which are distinguished by color. As for green oil, its solder mask ink is the oldest, cheapest and most popular.
In the processing of the printed circuit board, electronic product production includes plate making and several processes that need to go through the yellow light room, and the visual effect of green PCB board in the yellow light room is the best;
Secondly, in the SMT patch processing, the steps of tinning, patching and AOI verification all require optical positioning calibration, and the green baseboard has a more friendly instrument recognition;
Some testing processes rely on workers' observation (although now flying probe testing is mostly used instead of manual inspection), and under strong light, constantly staring at the board, green is friendly to the eyes;
The green printed circuit board is also relatively environmentally friendly. When the waste board is processed by high-temperature recovery, no toxic gas will be released. Other PCB colors, such as blue and black, are mixed with cobalt and carbon respectively because of their weak conductivity, which may cause short circuit risks.
In addition, for black, purple, blue and other colors, the color of the board printed circuit substrate is too dark, which will increase the inspection and maintenance difficulty of the motherboard, and it is not easy to control in terms of technology. Taking black board as an example, the black board is most likely to cause obvious color difference due to process and raw material ratio issues in production, leading to a high defect rate of PCB. The routing on black circuit boards is also not easy to identify, which will increase the difficulty of later maintenance and debugging. Many PCB factories do not use black PCBs much. Even in the military and industrial control fields where product quality requirements are extremely high, green PCB substrates are still the main choice. The color of the PCB board does not affect its performance. In summary, it is not difficult to understand why the PCB substrate color for printed circuit boards is mainly green.
