Many people use the color of the PCB to distinguish the quality of the board, but in fact, the color of the motherboard has little to do with the performance of the PCB. The higher the "appearance" value of a PCB board, the better it is used. It can be said that the quality of a PCB is not necessarily related to the color depth.

The color of the surface of the PCB board is actually the color of the solder resist. Solder resistance flux can prevent the occurrence of incorrect soldering of electrical components, and can also prolong the service life of devices and prevent oxidation and corrosion of device circuits. If you are familiar with the PCB boards of large companies such as Huawei and ZTE, you will find that the color is generally green, because green technology is the most mature and simple.

In addition to green, the colors of PCBs can be described as "fancy": white, yellow, red, blue, matte, and even chrysanthemum, purple, black, bright green, etc. White exists because it is a necessary color for making lighting products, while other colors are mostly used to label products. Throughout the entire stage of the company's research and development to product implementation, depending on the different uses of the PCB board, the experimental board may be purple, the key board may be red, and the internal components of the computer may be black, distinguished and marked by color. The most common PCB board is the green green board, also known as green oil, which has the oldest, cheapest, and most popular solder resist ink. Green oil not only has mature technology, but also has many advantages: in PCB processing, electronic product production includes making boards and pasting, during which several processes need to go through a yellow light chamber, and green PCB boards have the best visual effect in the yellow light chamber; Secondly, during SMT SMT chip processing, optical positioning calibration is required for the steps of tin coating, chip coating, and AOI calibration. The green base plate instrument is more user-friendly for recognition.

Part of the testing process relies on worker observation (although nowadays flying needle testing is mostly used instead of manual testing), constantly staring at the board under strong light, and the green color is eye friendly. Green PCBs are relatively environmentally friendly and do not release toxic gases when recycled at high temperatures.

Other PCB colors, such as blue and black, are mixed with cobalt and carbon respectively, due to their weak conductivity and the risk of short circuits.

The color is too dark, which often increases the difficulty of inspecting and repairing the motherboard. Taking black boards as an example, they are most likely to cause color differences due to process and raw material issues in production, resulting in a high PCB defect rate. The wiring of black circuit boards is difficult to distinguish, which increases the difficulty of later maintenance and debugging. Many PCB factories do not use black PCBs very much. Even in the military and industrial control fields, products with extremely high quality requirements still use green PCB substrates.

Next, let's talk about the impact of solder resist ink color on the board?

For finished products, the impact of different inks on the appearance of the board is mainly reflected in the issue of whether it looks good or not. For example, green includes sun green, light green, dark green, matte green, etc. If the color is too light, it is easy to see that the appearance of the board after the plug hole process is not good. Some manufacturers also have poor ink, resin and dye ratios, which can cause problems such as bubbles, and slight color changes can be detected; The impact on semi-finished products is mainly reflected in the difficulty of production, which is a bit complex to explain. Different colors of ink have different coloring processes, such as electrostatic spraying, spraying, and screen printing. The ink ratio is also different, and even slight errors in color can cause problems.

Although ink color has no effect on PCB boards, ink thickness has a significant impact on impedance, especially for water-based metal panels, which have extremely strict control over ink thickness; Red ink is easy to control in terms of thickness and bubbles. Covering the circuit with red ink can cover some defects, making it more beautiful in appearance. However, the downside is that the price is relatively expensive. When imaging, red and yellow exposures are more stable, while white is the most difficult to control.

In summary, color has no effect on the performance of the finished board, and its impact on PCB installation and other processes is relatively small; In PCB design, strict control of every detail in every step is the key to making a PCB a good board. PCB motherboards with different colors are mainly used to serve the product's sales, and it is not recommended to use PCB color as an important reference factor during PCB processing.