In the PCBA processing process, due to the complex process, various processing equipment and materials will be used, so there will always be some levels of pollution. Among them, the source of pollutants is mainly from tin slag and flux residues during processing. Wait, there are fingerprints, oil and dust, etc. Next, let us understand it in detail.

First of all, let’s talk about the tin dross contamination. There are two main reasons for the generation of tin dross. One is caused by the excessive amount of tin in the solder paste printing process, and the other is caused by the explosion of the solder joints of the board or components due to moisture, in which the amount of tin is too large. It may be caused by the problem of stencil mesh opening or the thinness of solder paste and the problem of printing spacing, and the dampness of the board or components is caused by the excessive humidity in the storage environment. In the PCBA processing process, only Avoiding the above problem points can reduce or avoid the generation of tin dross.

Flux residue contamination is caused by incomplete flux after soldering, and the problem of flux residue cannot be completely dealt with, because no matter what kind of flux cannot be completely volatilized during soldering, more or more There will always be some residue on the board, and the flux residue not only has a relatively high viscosity, it is easy to absorb dust and other pollutants, and it is also corrosive to a certain extent. If it is not cleaned in time, it will cause corrosion to the PCBA board. , which will cause great harm to the functionality and stability of the PCBA board. Therefore, it is necessary to deal with the flux residue in time after soldering. Generally speaking, washing the board is an effective way to deal with the flux residue.

In addition to the above two points, the operator's fingerprint oil is also one of the sources of pollution, so the operator must be asked to avoid touching the PCBA board with bare hands during PCBA processing. Pad oxidation is also a source of contaminants. Although PCBA substrates are prone to various contaminations during processing, fortunately, these contaminants can be removed by the board washing process.