Is The Color Of Pcb Board Important

Many people like to judge the quality of the motherboard based on the color of the PCB substrate. In fact, the color of the motherboard is not directly related to performance. The color of the surface of the PCB board is actually the color of a solder resist (also known as solder resist paint). Its function is to prevent the wrong soldering of the original electrical components during the welding process. At the same time, it has another function, which is to prevent the oxidation and corrosion of the welding components during use, and reduce the failure rate.

Under normal circumstances, PCB board parts are generally green, because the green process is the most mature and simple. But in extreme cases, there will be red, white, blue, yellow and matte colors board. And in more extreme cases there are black, purple, chrysanthemum, bright green board. Under normal circumstances, white PCB boards must be used for the production of lighting products. Most of the other colors are product grading systems. Different companies have different product grading way. Some use red to indicate experimental boards, some use blue to indicate key boards, and some use black to indicate boards used in computers.

The most common color of PCB board is green. Green solder resist ink is the oldest, cheapest and most popular. Generally speaking, the entire electronic board-level products have to go through the board making and patching process. There are several processes in the board making process that go through the yellow light room. The visual effect of green in the yellow light room is better, but this is not the main reason. When soldering in SMT, it needs to go through the tin and post and the final AOI verification. These processes all need optical positioning calibration. The green background color is better for the identification of the instrument.

Other common colors are red, yellow, blue and black. Due to process problems, many line inspections still rely on workers to see with their eyes (of course, most of them now use flying probes to test). Keeping the kanban under the eyes with strong light, this is a very tiring job. Green is relatively harmless to the eyes, so most of them use green.

The blue and black board are doped with cobalt and carbon respectively, and have a certain conductivity, so there is a risk of short circuit. The green PCB is more environmentally friendly, and it does not release toxic gases when used in high temperature environments.

In fact, if the board color is too dark, it will often increase the difficulty of inspection and maintenance of the motherboard. Take the earliest black PCB substrate as an example. In the process of washing the PCB, black is the most likely to cause color difference. If the raw materials used in the PCB factory and the self-made process are slightly different, the PCB defect rate will increase due to color difference. Because the circuit traces of the black PCB are difficult to recognize, it will increase the difficulty of later maintenance and debugging. Generally, motherboard manufacturers will not easily use black PCBs. Therefore, we see that even products with high quality requirements, such as military and industrial products, only use green PCB substrates.

So how does the color of solder resist ink affect the board? The ink has no effect on the finished product, but it has a great influence on the semi-finished product, mainly on the ease of making the semi-finished product. To add, some people will say that the color still affects the PCB board. Indeed, there is a little color difference between matte green, sun green, dark green and light green. If the color is too light, it is easy to see the appearance of the board after the plug hole process is not good. If the color is too dark, some manufacturers' ink is not good enough and the ratio of resin and dye is wrong, there will be problems such as bubbles. Seriously, the ink will be lost during final curing. This is a problem with the ink ratio. You can see a slight change in color, and you can't feel it without years of experience.

Although the color of the ink has no effect on the board, the influence of the thickness of the ink on the impedance is very large, especially for the gold board parts. The thickness control of the board ink is very strict. According to experience, if using red ink, bubbles and thickness are easier to control.

In summary, the color has no effect on the performance of the motherboard, and it does not play a very important and decisive role in PCB design. However, in PCB design and production, strict control of every detail in every link is a prerequisite for whether a PCB board is a good board. We know that PCB boards of different colors are more for the sale of products. Therefore, it is not recommended that using the PCB color as a reference factor when purchasing a motherboard.