First, in principle, the higher the wave crest, the larger the solder surface in contact with air, the more oxidation, and the more slag. Therefore, the peak should not be too high, generally do not exceed the thickness of the printed circuit board direction 1/3, that is, the top of the wave to exceed the printed circuit board welding surface, but can not exceed the surface components.
Secondly, if the wave crest is unstable, the liquid solder can easily bring air into the molten solder when it falls back from the peak, accelerating the oxidation of tin during the wave crest soldering process, the copper deposited on the surface of the printed circuit board and the copper on the pins of the electronic components will continuously dissolve into the molten solder. CU6SN5 intermetallic compound is formed between copper and tin. The melting point of CU6SN5 is above 500 ° C, so it exists in solid state. At the same time, because the density of the compound is 8.28 g/cm3, and the density of SN63PB37 solder rod is 8.8 g/cm3, so the compound will generally appear as tofu dregs floating on the surface of liquid solder.
Finally, the work of copper removal is very important. Operation as follows: Stop the wave, the heating device of the tin furnace normal operation, first of all the tin furnace surface all kinds of residue clean, exposed mercury-like mirror state. Then lower the temperature of the furnace to 190-200 ° C (when the solder is still liquid) and stir the solder with an iron spoon or other tool for 1-2 minutes to help the tin-copper compound inside the solder float and stand for 3-5 hours. Because of the small density of tin-copper compounds, after static tin-copper compounds will naturally float on the surface of solder, at this time with iron spoon and other tools can be surface of tin-copper compounds clean.
If there is any problem can find us to help solve the problem, there is soldering problem, find Yongjia Run Tin!
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