"Cleaning" is often overlooked in the PCBA manufacturing process of circuit boards (circuit boards), and cleaning is not a critical step. However, with the long-term use of the product on the client, the problems caused by the previous invalid cleaning caused many failures, and the return of repairs or recalled products caused a dramatic increase in operating costs.
Circuit board (circuit board) PCBA cleaning function.
The PCBA (printed circuit assembly) production process passes through multiple process stages, and each stage is contaminated to varying degrees. Therefore, various deposits or impurities remain on the surface of the circuit board (circuit board) PCBA. These contaminants will reduce product performance , Or even cause product failure. For example, in the process of soldering electronic components, solder paste, flux, etc. are used for auxiliary welding, and a residue is generated after welding. The residue contains organic acids and ions. Among them, organic acids will corrode the PCBA of the circuit board (circuit board), and The presence of electrical ions may cause a short circuit and cause product failure.
There are many kinds of contaminants on the PCBA of the circuit board (circuit board), which can be categorized into ionic and non-ionic types. When ionic pollutants come into contact with moisture in the environment, electrochemical migration occurs after energization, forming a dendritic structure, resulting in a low resistance path and destroying the PCBA function of the circuit board (circuit board). Non-ionic pollutants can penetrate the insulating layer of the PCB and grow dendrites under the surface layer of the PCB. In addition to ionic and non-ionic contaminants, there are granular contaminants, such as solder balls, floating points in the solder bath, dust, dust, etc. These contaminants will cause the quality of the solder joints to deteriorate, the solder joints will be sharpened and generated Poor phenomena such as blowholes and short circuits.
With so many pollutants, which ones are the most concerned about? Fluxes or solder pastes are commonly used in reflow and wave soldering processes. They are mainly composed of solvents, wetting agents, resins, corrosion inhibitors, and activators. Thermally modified products must exist after soldering. These substances Dominant in all pollutants, in terms of product failure, the residue after welding is the most important factor affecting product quality, ionic residues are easy to cause electromigration and reduce the insulation resistance, and rosin resin residues are easy to adsorb The contact resistance increases due to dust or impurities, and the open circuit fails in severe cases. Therefore, strict cleaning must be performed after welding to ensure the quality of the PCBA of the circuit board (circuit board).
In summary, the cleaning of the PCBA of the circuit board (circuit board) is very important. "Cleaning" is an important process directly related to the quality of the PCBA of the circuit board (circuit board) and is indispensable.
