Importance Of Cleaning Of Printed Circuit Components After Soldering
The PCBA production process undergoes multiple process stages, and each process stage is contaminated to varying degrees. Therefore, various precipitates or impurities remain on the PCBA surface, which may reduce product performance or even cause the product to fail. For example, during soldering of electronic components, solder paste, rosin flux etc after soldering through SMT processing, residues are obtained, which contain organic acid residues and ions. These residual organic acids will corrode the processed PCBA or PCB circuit board substrate. The presence of electrical ions may cause a short circuit and result in product failure.
In daily life, we will pay attention to all kinds of quality control in SMT patch processing, and ignore the cleaning process after PCBA manufacturing, most companies do not pay much attention to the cleaning process, and believe that cleaning is not a key technical step. However, the ineffectiveness caused by the pre-cleaning of the problematic products used on the client side for a long time leads to many failures, and the maintenance or recall of the product causes a sharp increase in operating costs.
Ionic pollution and non-ionic pollution have always been important sources of pollution on PCB and PCBA. Ionic contaminants enter, come into contact with moisture in the environment, and electrochemical migration occurs after energization, and a dendritic structure is formed, resulting in a path of low resistance, so destroying the PCBA function of the circuit board. Non-ionic contaminants can penetrate the insulating layer of PCB and form growth dendrites under the surface layer of the PCB. In addition to ionic and non-ionic contaminants and particulate contaminants, such as solder balls, solder bath floats, dust, dirt, etc., these contaminants will lead to lower solder joint quality, solder joint icicles to produce porosity, short circuit and many other defects phenomenon.
Because in China's current SMT patch processing, flux or solder paste can generally be used in reflow soldering and wave soldering processes. They are mainly composed of solvents, wetting agents, resins, corrosion inhibitors, and activators. There must be thermally modified products after welding. From the perspective of product structure failure analysis, the residue after welding is the most important social impact factor affecting the company's product and service quality management. The rosin resin residue is easy to absorb dust or impurities and causes a gradual increase in resistance. In severe cases, it may lead to open circuit failure, so after welding, strict cleaning must be carried out.
In summary, the cleaning of PCBA is very important. "Cleaning" is an important process, which is directly related to the quality of circuit board and is indispensable.
