Advantages of the no-clean process in PCBA processing

1. Introduction:

Clean-free refers to the use of low solid content, non-corrosive flux in PCBA processing, soldering in an inert gas environment, the residue on the circuit board after soldering has no corrosion and has a very high surface insulation resistance, generally does not need to be cleaned to meet the standard of ion cleanliness, can directly enter the next PCBA processing process technology. Next, Suzhou Nofer will share with you the matters related to the no-clean process in PCBA processing, hoping to bring you some help!

In the field of PCBA (Printed Circuit Board Assemblies) processing, no-clean processes are becoming a technology that is gaining traction. The traditional cleaning process requires the use of chemical solvents to clean the circuit board after PCBA processing to remove impurities such as flux residue generated during the soldering process. However, the no-clean process omits this cleaning step and offers a number of significant advantages.

Second, the advantages of environmental protection

Reduce the use of chemical solvents

The traditional cleaning process relies on a large number of chemical solvents, such as freons, alcohols, etc. The production, transportation and use of these chemical solvents can cause environmental pollution. The no-clean process avoids the use of these chemical solvents and reduces the emission of chemicals directly to the environment at the source.

Reduce the pressure of waste disposal

The cleaning process produces waste containing flux residues and chemical solvents. These wastes need to be treated in order to meet environmental requirements. Since there is no cleaning step, the no-clean process will not produce this kind of cleaning waste that requires special treatment, which reduces the pressure on the environment in the waste treatment process.

1. Save a lot of cleaning labor, equipment, site, materials (water, solvent) and energy consumption;

2. Save man-hours and improve production efficiency;

3. Advanced production technology: spray coating, inert gas protection;

4. Avoid damage to welding components due to cleaning stress; 5. Conducive to environmental protection;

Third, the advantages of material cost control

Save on cleaning equipment and associated costs

The traditional cleaning process requires special cleaning equipment, such as ultrasonic cleaning machines, spray cleaning machines, etc. The acquisition costs, installation costs, maintenance costs, and operating costs (e.g. energy consumption) of these devices are considerable. The no-clean process does not require these cleaning equipment, and enterprises can use this part of the funds for other production links or R&D investment.

Reduce labor costs

The cleaning process requires specialized operators to operate the equipment and inspect the cleaning quality. The no-clean process eliminates this step, reducing the need for associated operators and reducing labor costs.

1. Low solid content: less than 2%, solid content of traditional flux: 5%~40% does not contain rosin components;

2. Non-corrosive, high surface insulation resistance, halogen components are not allowed, high insulation resistance: 1.0X10^11;

3. Solderability requirements: non-water-soluble acetic acid series has a certain ability to eliminate oxides and maintain a certain degree of activity.

4. Meet the requirements of environmental protection: non-toxic, no strong irritating odor, basically do not pollute the environment, and operate safely.

In the implementation of the no-clean PCBA processing and soldering process, the solderability and cleanliness of printed circuit boards and components are the aspects that need to be controlled. In order to ensure solderability, PCBA processing manufacturers should store it in a constant temperature and dry environment under the premise of requiring suppliers to ensure solderability, and strictly control the use of it within the effective storage time. In order to ensure cleanliness, the environment and operation specifications should be strictly controlled during PCBA processing to avoid man-made pollution, such as handwriting, sweat, grease, dust, etc.

Fourth, PCBA processing without cleaning process

1. Flux coating process: In order to obtain a better no-cleaning effect during PCBA processing, the flux coating process must strictly control two parameters, namely the solid content of flux and the amount of coating.

2. Spray coating:

(1) Due to the high solvent content of no-clean flux, it is particularly volatile, which leads to the increase of solid content. Therefore, the spray method can effectively solve the problem of flux volatilization.

(2) Due to the extremely low solid content of no-clean flux, it is not conducive to foaming coating.

(3) The spray method can control the amount of flux coating, and the coating is uniform.

(4) The flux spraying system adopts the scanning spray method, and the limit proximity switch and the board optical eye are combined to control, and the PCBA board automatically detects the induction spray according to the speed and width of the PCBA. The wetting range of the flux can achieve the best effect, imported nozzles and rod cylinders, and special drive control systems, which are accurate and reliable.

(5) It is equipped with adjustable direction and pneumatic air knife to blow off the excess flux during spraying into the recovery box to prevent the flux from entering the preheating area and ensure production safety;

(6) It must be noted that because the flux contains more flammable solvents, the solvent vapor emitted during spraying has a certain risk of deflagration, so the PCBA processing equipment needs to have good exhaust facilities and necessary fire extinguishing equipment.

Fifth, the advantages of production efficiency

Shorten the production cycle

The cleaning process needs to occupy a certain amount of production time, including the preparation time of the cleaning equipment, the cleaning time, and the drying time after cleaning. The no-clean process eliminates this time, resulting in shorter PCBA production cycles. This is of great significance for improving the production efficiency of enterprises and quickly responding to market demand.

Reduce the complexity of the production process

In the traditional PCBA process, the addition of a cleaning process makes the production process more complex. It is necessary to coordinate the connection between the cleaning process and other processes, such as the transportation of the cleaned circuit board and the prevention of secondary contamination. The no-clean process simplifies the production process, reduces potential risks in the production process, and improves the stability of production.

Sixth, the advantages of quality and reliability

Reduces potential damage during cleaning

During the cleaning process, especially when using mechanical cleaning methods (such as ultrasonic cleaning), it may cause a certain degree of damage to the precision components and solder joints on the PCBA. The no-clean process avoids potential damage during this cleaning process and improves the quality and reliability of the PCBA.

Consistent solder joint quality

No-cleanflux creates good solder joints during the soldering process and is not affected by the cleaning process as it does not need to be cleaned. This consistent quality of solder joints helps to improve the overall performance and service life of the PCBA.

VII. Conclusions

To sum up, the no-clean process in PCBA processing has obvious advantages in terms of environmental protection, cost control, production efficiency and quality reliability. With the continuous development of electronic manufacturing technology, the no-clean process is expected to be more widely used, promoting the development of the PCBA processing industry in the direction of more efficient, environmentally friendly and high-quality.

While the no-clean process has many advantages in PCBA processing, it also faces some challenges in practical applications. For example, the operation specifications for operators are more stringent, because there is no cleaning link to compensate for errors in operation. Quoting the point of view in the article, in order to ensure solderability, it is necessary to strictly control the storage environment of printed circuit boards and components, which may affect the processing quality of the entire PCBA once it is not properly operated.

8. From the perspective of materials, the characteristics of low solid content and high solvent content of no-cleanflux make it necessary to use the spray method in the coating process, and although the spray method can solve the problems of flux volatilization, the deflagration danger of solvent vapor during spraying increases the safety risk of the production environment. This requires enterprises to be equipped with good exhaust facilities and fire extinguishing appliances when adopting the no-clean process, which undoubtedly increases the safety cost of enterprises.

In addition, when it comes to marketing, some companies with deep-rooted traditional beliefs may be skeptical about no-clean processes. They are accustomed to the process and quality control of the traditional cleaning process, and have doubts about whether the no-clean process can truly ensure the quality and reliability of the PCBA. However, with the further development of technology and the emergence of successful cases, this perception is expected to gradually change.

As the industry evolves, standards and specifications related to no-clean processes also need to be continuously improved. At present, some index requirements for no-clean processes, such as the solid content of flux and solderability requirements, are clearly stipulated, but with the innovation of technology and the expansion of application scenarios, these standards may need to keep pace with the times. For example, when faced with new components or special PCBA processing requirements, existing standards may not be able to fully meet the requirements. Therefore, enterprises, research institutions and regulatory authorities in the industry need to work together to continuously optimize the relevant standards and specifications of the no-clean process, so as to promote the healthy and wide application of the no-clean process in the PCBA processing industry.