In the SMT solder paste soldering process, the solder paste printing steel mesh needs regular offline cleaning, which is an indispensable process and operation mode in the SMT process. The cleanliness of the SMT steel mesh directly affects the graphic accuracy and tin of the solder paste printing. The amount of paste, which guarantees the quality of solder paste soldering and reduces the defects of solder joints, is especially important for high-precision fine-pitch printing.

Many manufacturers' existing stencil cleaning equipment is often a traditional pneumatic sprayer, which uses organic solvent-based cleaning agent or alcohol to clean the steel mesh. This method solves the problem that the original manual cleaning reliability is not high and the cleaning degree is not guaranteed. problem. The automatic cleaning method achieves continuous and complete cleaning of the steel mesh, but with the improvement of environmental protection and safety requirements, the way of cleaning the steel mesh with solvent-based cleaning agent is gradually changing and changing, and the use of environmentally friendly water-based cleaning agent is combined with steel. The cleaning of the steel mesh by the net cleaning machine has become the direction and trend of SMT printing steel mesh cleaning.

The original pneumatic sprayer uses volatile organic solvent as the cleaning material because the solvent has a low flash point and high volatility, and the evaporation loss of the solvent during operation is large. The high concentration of the solvent vapor has a high safety risk, and a deflagration accident often occurs. And the cost of cleaning agents is high. By replacing the solvent-based cleaning agent with an environmentally friendly water-based cleaning agent, the solder paste steel mesh can be completely cleaned with the same working time and efficiency. Of course, this operation method has the defect of incomplete water-based cleaning process because the water-based cleaning agent itself The characteristics cannot be dried under normal temperature conditions, so the steel mesh needs to be manually rinsed or cleaned with a non-woven fabric to achieve a usable state. This mode of operation will greatly reduce the cost of the cleaning agent, and obtain a safe and environmentally friendly working environment, completely avoiding solvent deflagration, but merely increasing the amount of manual rinsing or wiping work by the operator.

A few pneumatic sprayers have the function of common chamber cleaning and rinsing. In layman's terms, the stencil is cleaned first and then rinsed in the same chamber. The machine is equipped with a cleaning tank and a rinse tank, and the cleaning and rinsing rotation work. This type of machine can achieve the cleaning and rinsing functions of water-based cleaning agents, meeting the requirements of the complete process of water-based cleaning agents, but because of the cross-contamination and cross-linking caused by co-cavity cleaning.

It is very well understood that when cleaning, the inner wall of the chamber and the steel mesh are contaminated with a large amount of water-based cleaning agent due to the spray cleaning agent. When the water-based cleaning agent is cleaned, the cleaning liquid is discharged into the cleaning tank. At this time, the water-based cleaning agent adhered to the inner wall of the chamber and the surface of the steel mesh, and the cleaning agent remaining in the pipeline will bring the water-based cleaning agent into the rinsing liquid as the rinsing progresses. When the next stencil is cleaned, the water rinsing liquid is adhered and retained in the chamber, and this part of the rinsing water is brought into the cleaning agent to dilute the water-based cleaning agent. As the stencil continues to clean and rinse, the concentration of the cleaning agent will gradually decrease, and the contamination of the rinsing water will gradually increase, resulting in two-way dilution and contamination of the cleaning agent and the rinsing water. The size of the cavity and the amount of residual liquid remaining in the pipe. Despite this, this type of operation is much less expensive than solvent cleaning, and efficiency is also improved.

The best way to operate is to use a dedicated stencil ultrasonic cleaner with separate ultrasonic cleaning tanks, separate rinsing tanks, and separate drying tanks. In this way, when the water network cleaning of the steel mesh is carried out, only the water-based cleaning agent adhered to the liquid from the cleaning tank to the rinsing tank steel mesh itself is lost. Generally, the liquid separation is only a few tens of grams, so the cleaning agent The loss will be very small. The rinsing tank can ensure the cleanness of rinsing because the cleaning agent has a small amount of liquid contamination. This type of operation avoids the adverse effects of the two-way dilution pollution of the common chamber cleaning rinse cleaning agent and the rinse water, and fully exerts the outstanding advantages of the long life of the water-based cleaning agent. In this way, it is possible to form a water-based cleaning steel mesh with an efficient and low-cost optimal operation method. Although such equipment is higher than the pneumatic sprayer, for actual operation, the operation can be exceeded for half a year to a year and a half. The low-cost operation of the water-based cleaning agent is recovered, and long-term efficiency, cleaning effect and low-cost operation mode will be obtained.

From the perspective of process design, to meet the technical requirements of water-based cleaning effect and efficiency of steel mesh, the corresponding stencil cleaning machine and water-based cleaning agent are selected and configured to achieve the complete process of water-based cleaning, and the water-based cleaning agent is safe and environmentally friendly. The long-life characteristic advantage, under the cooperation and guarantee conditions of the process, equipment and water-based cleaning agent, greatly reduces the use cost and improves the efficiency to obtain a high level of clean and dry steel mesh.