SMT reflow oven with nitrogen (N2) is the most important role in reducing the welding surface oxidation, improve the wettability of welding, because nitrogen is a kind of inert gas, not easy to produce compounds with metal, it can also cut off the oxygen in the air and metal contact at high temperature and accelerate the oxidation reaction.
Firstly, the principle that nitrogen can improve SMT weldability is based on the fact that the surface tension of solder under nitrogen environment is less than that exposed to atmospheric environment, which improves the fluidity and wettability of solder.
Secondly, nitrogen reduces the solubility of oxygen in the original air and the material that can pollute the welding surface, greatly reducing the oxidation of high temperature solder, especially in the improvement of the second side backwelding quality.
Nitrogen is not a panacea for PCB oxidation. If the surface of a component or circuit board is heavily oxidized, nitrogen will not bring it back to life, and nitrogen is only useful for minor oxidation.
Advantages of solder reflow oven with nitrogen:
Reduce furnace oxidation
Improve welding capacity
Enhance solderability
Reduce the cavity rate. Because solder paste or solder pad oxidation is reduced, the flow of solder is better.
Disadvantages of SMT soldering machine with nitrogen:
burn
Increases the chance of tombstone generation
Enhanced capillarity (wick effect)
Post time: Aug-24-2021