Many people in the selection of solder paste often wonder, do not know how to identify the quality of solder paste is good or bad, the simplest way to sample, see the welding effect. If the solder paste appears in the printing process, bridge, skin, adhesion is not enough, fuzzy these several bad conditions, can be analyzed. What are the causes of these cases, and how to solve them? The bridge, the occurrence of the cortex may be the solder paste metal ratio is not uniform or the tin powder particles are too large; Occurs in the cortex, solder paste flux is too strong, if there is lead solder paste, may be too high lead content. Insufficient adhesive force may be the reason that the solvent in the solder paste is easy to volatilize and the metal ratio of the solder paste is too high.

There are many reasons why lead-free solder paste dries, such as bad formula, inappropriate ambient temperature and humidity, high temperature, fast solvent volatilization. Humidity is too large, the solder paste absorbs water, and the rosin effect in the solder paste to dry it, lead solder paste wettability is better than lead-free, this is determined by the metal, there is no way, in order to achieve the same welding effect is only in the welding paste up and down, that is, to enhance the activity of the lead-free solder paste, so that it will increase the corrosion of the solder paste surface, so that the surface area of the tin powder increases, As a result, the viscosity increases and, in the worst case, dries out. But in general, this problem has now been solved, especially with halogen solder paste, basically will not do this!