In the production and manufacturing process of the manufacturer, in principle, it is necessary to avoid contact with the air as much as possible, and the less the area and frequency of contact with the air, the better. The contact of lead-free solder paste
with air will cause the internal metal tin powder to be oxidized by oxygen in the air, resulting in the failure of solvents, fluxes and other components, affecting the performance. Not only is it as simple as oxidation, but the actual test results of lead-free solder paste manufacturers also show that too much contact with air will cause the flux to fail, and the solvent in the flux will evaporate into the air too much.
Solder paste manufacturers suggest that SMT manufacturers should use up the solder paste at one time after the solder paste has warmed up in the actual use process, otherwise taking a little bit each time will cause the solder paste to solidify. We open the lid of a bottle of solder paste and close the inner lid of the bottle immediately after taking out the solder paste inside. Do not open the lid of the solder paste bottle frequently. Frequent opening and closing or opening the lid will quickly cause the lead-free solder paste to lose its effectiveness. When we use a bottle of solder paste, if the actual quantity taken out is not large, the inner cap should be tightly closed immediately after taking out the solder paste, and the inner cap of the solder paste bottle should be pressed down forcibly so that the inner cap and the solder paste can interact with each other. Contact to remove the internal air, this can prevent the air from entering the bottle after the cap is opened, and even after the cap is tightened, a small amount of air will remain inside the bottle to cause oxidation of the lead-free solder paste. The removed solder paste should be put into the SMT soldering process as soon as possible. SMT solder paste printing should be continuous without stopping, and the removed solder paste should be used up at one time. In the actual use process, the SMT solder paste manufacturer can estimate the actual quantity to be used according to the number of circuit boards to be processed. To avoid the amount of rewarming too much, it will be put into the refrigerator for refrigeration after rewarming. Frequent heating and cooling will seriously affect the performance of solder paste.