How to choose the color of PCB board?
PCBs come in many colors, including green, blue, red and black. These are the more commonly used colors. When we get a PCB board, the most intuitive thing is to see what color the ink on the board is, which is what we usually refer to as the PCB color.
Among them, green is the one most commonly used by engineers and is more familiar to people. But how should we choose the color of PCB for different PCBs? Why do we prefer green?
1.Green PCB: Green is the most common PCB color, and it is also the most economical and widely used choice. This is because in the traditional FR-4 substrate manufacturing process (fiberglass reinforced epoxy resin), a green photosensitive matrix is used for printed circuit board patterns and labels to form a solder mask. The green color provides good contrast, making logos and trace lines on the circuit board clearly visible.
Simply put, there are two reasons: low cost and good for your eyes. The green part is called solder mask. The ingredients are resin and pigment, and the green part is green pigment. However, with the development of modern technology, many other colors have also been expanded. It's no different than decorative paint. The solder mask is adhesive and liquid before soldering and printing on the PCB. After printing on a PCB, the resin is hardened by heat and eventually "cured." The purpose of resistance soldering is to prevent moisture, oxidation and dust on the PCB. The only area not covered by the solder mask is usually called the pad and is used for solder paste.
Generally speaking, we choose green because it does not irritate the eyes. It is not easy for production and maintenance personnel to stare at PCBs for a long time. In terms of design, commonly used colors include yellow, black and red. Various colors are applied to the surface after manufacturing.
Another reason is that the commonly used color is green, so the factory has the most spare green paint, so the cost of oil is relatively low. This is also because when repairing PCB boards, different wiring is easier to distinguish from white, while black and white are relatively difficult to see. In order to distinguish product levels, each factory uses two colors to distinguish high-end and low-end series.
2. Red PCB: Red PCB is very common in certain specific applications, such as high-end communication equipment, military electronic products, etc. Red PCBs usually use high-temperature-resistant red photosensitive dyes. These dyes have good thermal stability and weather resistance, and are suitable for applications in high temperatures and harsh environments.
Generally speaking, while the color of the solder mask does not have a significant impact on the board, the thickness of the painted surface has a significant impact on the production impedance. According to production experience, the bubbles and thickness of red solder mask are usually easy to control, and the production process is relatively simple. This is also one of the reasons why red and yellow boards are not high-end enough in the industry.
3.Blue PCB: Blue PCB is also relatively common and is usually associated with specific brands and products. Blue PCB uses blue photosensitive dye to form a solder mask layer, which has good appearance and recognition. Blue solder masks lack hardness and are prone to scratches, resulting in an increase in defective products produced by PCB manufacturers. In addition, the blue solder resist paint has high fluidity and is prone to oil accumulation and uneven oil. Therefore, it needs to be laid flat during the production process and cannot be placed vertically, which takes up space.
4. Black PCB: It is common in some high-end applications, such as high-performance computers, audio equipment, etc. Black PCB can bring quality and professionalism to the board, while black also has good heat dissipation properties and is suitable for applications that require high power processing.
Generally speaking, black and blue circuit boards are made by adding cobalt and carbon to the solder mask, which may look more high-end, but have a certain conductivity during use and pose the risk of short circuits. In addition, cobalt and carbon easily emit toxic gases in high-temperature environments and are not environmentally friendly during use or post-processing.
At present, there are also a few manufacturers on the market using black PCB boards. We think there are two reasons for this: 1. It looks more high-end; 2. The wiring inside the blackboard is not easy to see, which brings some difficulties to plagiarizing the blackboard.
To sum up, it is generally better to use green PCB.
However, although green PCB boards are the most common, customers can customize the color of the PCB boards according to their own needs. For example, a red PCB can improve the visual effect, while a black PCB can make the board look more high-end and technological. Therefore, the choice of PCB board color can be completely based on the customer's needs and design requirements.