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The reason why PCBA is almost green and its cleaning effect?
PCB Tech
The reason why PCBA is almost green and its cleaning effect?

The reason why PCBA is almost green and its cleaning effect?

2021-11-05
View:34
Author:Downs

1. PCBA board is basically the green reason

The society is developing rapidly, the market for electronic products is also very hot, and there are more people joining the industry, so many will choose to find electronic OEMs to cooperate, provide production materials and raw materials, and let PCBA factories process them. At this time, some friends may have questions, why are PCBA boards basically green? Next, I will introduce to you.

       The society is developing rapidly, the market for electronic products is also very hot, and there are more people joining the industry, so many will choose to find electronic OEMs to cooperate, provide production materials and raw materials, and let PCBA factories process them. At this time, some friends may have questions, why are PCBA boards basically green? Next, I will introduce to you:

       In fact, the color on the PCBA board is the color of the solder resist. The main function of the flux is to prevent mis-soldering of components, delay the service life of the device, and prevent oxidation and corrosion of the device circuit. In addition to the common green solder mask, PCBA boards also have white, yellow, red, blue, matte colors, and even chrysanthemum, purple, black, bright green and other colors.

pcb board

       There is also a reason why green is so widely used. In PCB processing, electronic product production includes board making and post filming. During the process, there are several processes to go through the yellow light room, and the visual effect of the green PCBA board in the yellow light room is very good; In the production process of SMT patch processing, the steps of tinning, patching and AOI verification all require optical positioning and calibration. The green bottom plate is better than other colors when it is recognized, and the green PCBA board is more environmentally friendly and is discarded. No toxic gas will be released when the board is recycled at high temperature.

Second, the role of PCBA cleaning

PCBA cleaning can improve the quality of the circuit board, otherwise it will affect the stability of the product. Next, I will introduce the role of PCBA cleaning.

PCBA cleaning can improve the quality of the circuit board, otherwise it will affect the stability of the product. Next, I will introduce the role of PCBA cleaning:

1. Appearance and electrical performance requirements: The most intuitive impact of PCBA pollution is appearance. If it is placed or used in a high-temperature and high-humidity environment, the residue may absorb moisture and turn white. Due to the widespread use of lead-free chips, miniature BGA, chip scale packaging (CSP) and 01005 in components, the distance between the component and the circuit board is reduced, the size is reduced, and the assembly density is increased. If halides are hidden under components that cannot be cleaned, local cleaning may have catastrophic consequences due to the release of halides.

2. Requirement for three anti-paint coatings: the resin residues that have not been removed before the PCBA surface coating will cause delamination or cracking of the protective layer; the active agent residues may cause electrochemical migration under the coating, which will lead to the coating anti-corrosion The protection fails. Studies have shown that cleaning can increase the adhesion rate of the coating by 50%.

3. No-cleaning also requires cleaning: According to current standards, the term "no-cleaning" means that from a chemical point of view, residues on the circuit board are safe, will not have any impact on the circuit board production line, and can remain in the circuit On the board. Corrosion, SIR, electromigration and other special detection methods are mainly used to determine the halogen/halide content, and then determine the safety of the no-clean components after the assembly is completed.

       The above introduction, I hope it can help everyone, using PCBA processing factory with low solid content no-clean flux, there will still be more or less residues. For products with high reliability requirements, no residues or contaminants are allowed on the circuit board. For military applications, even electronic components need to be cleaned.