Pcb manufacturer china processing cleaning method and technics process
In Pcb manufacturer china, most of the cleaning methods of printed circuit components are classified into the properties of the solution medium used for cleaning, and are mainly classified into three types: solvent cleaning method, semi-water cleaning method and water cleaning method.
Solvent cleaning method
Batch solvent cleaning technics. The batch cleaning technics is also called Intermittent cleaning in Pcb manufacturer china. The main technics flow is: placing the printed circuit component to be cleaned in the steam zone of the cleaning machine. Since the vapor zone is surrounded by a condensation pipe, the solvent located in the lower part of the vapor zone is heated to become a vapor state and rise to the surface of the cooled component, it is condensed into a solvent and acts with contaminants on the surface of the component to remove contaminants as the droplets fall. After the cleaned component stays in the vapor zone for 5 to 10 minutes, the cleaned liquid recycled by the solvent vapor is condensed to spray the component to wash away the pollutants.
When the surface temperature of the component staying in the vapor zone reaches the vapor temperature in Pcb manufacturer china, the surface no longer produces condensate, and the assembly is clean and dry and can be taken out. The cleaning method of the cleaning method has high cleanliness and is suitable for use in small batch production, which is suitable for application in the printed circuit assembly is not seriously polluted and the cleaning requirements are high. Its operation is semi-automatic, and there is a small amount of leakage of solvent vapor, which has an impact on the environment.
The main points of the batch solvent cleaning technics include the following aspects.
The boiling tank should contain a sufficient amount of solvent to promote uniform and rapid evaporation. Care should also be taken to remove the residue from the boiling tank.
There is a cleaning workbenchin the boiling tank to support the cleaning load; to keep the contaminated solvent at a safe height under the horizontal shelf of workbench, so that the solvent will bring into pollution to another solvent tank when the basket with the cleaning load is raised and lowered. .
The solvent tank should be filled with solvent so that the solvent can always flow into the boiling tank.
When the equipment is started, there should be sufficient time to form a saturated vapor zone and check to make sure that the condensing coil reaches the cooling temperature specified in the operating manual before starting the cleaning operationin Pcb manufacturer china.
Periodically replace the solvent in the boiling tank with fresh solvent depending on the using amount.
Continuous solvent cleaning technics. The continuous cleaning technics is suitable for high-volume and assembly line production. The cleaning quality is relatively stable. Since the operation is fully automatic, it is not affected by human factors. In addition, in the continuous cleaning technics, a mechanical decontamination method of high-pressure oblique jet and fan-shaped jet can be added, which is particularly suitable for the cleaning of surface-mounted circuit boards in Pcb manufacturer china.
Characteristics of continuous solvent cleaning technology.Continuous cleaners generally consist of a very long vapor chamber in Pcb manufacturer china, which is divided into several small vapor chambers to accommodate the solvent placement, solvent boiling, spray and solvent storage, and sometimes the components are immersed in boiling solvent. . Typically, the assembly is placed on a continuous conveyor belt that operates at different speeds depending on the type of SMA and passes through the steam chamber Solvent distillation and agglomeration cycles are all carried out in the machine. The cleaning procedure and cleaning principle are similar to batch cleaning, except that it is clear that the procedure is carried out in a continuous structure.
The key to cleaning SMA with continuous technology is to choose a satisfactory solvent and the best cleaning cycle.
Continuous solvent cleaning systemstypes. Continuous cleaning machines can be classified into the following three types according to the cleaning cycle.
Vapor → spray → vapor cycle. This is the most common cleaning cycle in continuous solvent cleaners. The assembly enters the vapor zone first, then enters the spray zone and is finally sent through the vapor zone. Spray up and down from the bottom and top in the spray area. This type of washing machine combines nozzles offlat, narrow fan and wide fanshape, and is sprayed with high pressure and spray angle control in Pcb manufacturer china.
Spray → immersion boiling → spray cycle. Continuous solvent cleaners with this type of cleaning cycle are primarily used for SMAs that are difficult to clean. The components to be cleaned are first sprayed obliquely, then immersed in the boiling solvent, then tilted to spray, and finally the solvent is removed.
Spray → immersion boiling with spray → spray cycle. A washing machine using this type of cleaning cycle is similar to the second type of cleaning machine except that a solvent spray is added to the boiling solvent. Some also provide a nozzle in the solvent that is submerged in boiling to form a solvent turbulent flowin Pcb manufacturer china. These are all intended to further enhance the cleaning effect.
The advantages of boiling ultrasonic cleaning. The effect is comprehensive, the cleanliness is high; the cleaning speed is fast, the productivity is improved; the surface of the component to be cleaned is not damaged; the chance of contact with the solvent by the hand is reduced, the work safety is improved, and the part which cannot be reached by other methods can be cleanedin Pcb manufacturer china.
At the same time, because ultrasonic waves have a certain penetrating ability, they often enter the inside of the device through the package of the device and destroy the solder joints of the transistor and the integrated circuit. Therefore, many countries in the world have clearly stipulated that military electronic products should not use boiling ultrasonic cleaning. China’s GJB3243 – military standard also stipulates that military electronic products are not allowed to use ultrasonic cleaning of printed circuit components in Pcb manufacturer china.
The above is the solvent cleaning method shared by the smt processing plant, more information visit:https://www.automotivepcba.com
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