无铅波峰焊钎料氧化渣动态形成特点

Dynamic Characteristic of the Solder Dross Form During Lead-free Wave Soldering

按照分布规律,将锡炉熔融钎料表面氧化物分为A～E5个氧化物区,分析了各区域氧化物的特点,研究了A、B2个区氧化渣的动态形成过程。A区氧化渣是波峰的瀑布效应引起的,主要在前喷嘴与前方炉壁之间的区域形成,其形成原因有剪切成渣、氧化物夹带钎料运动堆积成渣和负压吸氧3种。B区氧化渣由氧化膜包裹钎料堆积而成,是两喷嘴间液面波动和钎料定向流动共同作用的结果。

In this paper, according to the distribution rules, the oxide area on the surface of fusing solder in the pot is divided into five oxide area A-E. The characteristic of each area of oxide is analyzed. The dynamic establishment of dross in both A and B areas is analyzed. The dross in A area is caused by Waterfall Effect of wave, and is mainly generated in the area between the nozzle and pot wall. The resons to cause this dross include shearing of the interface of oxide and solder, the movement of oxide included solder, and negative pressure inhaling of oxygen. Dross in B area is generated during oxide film moving, stacking and covering the solder, and this is the result of both the fluctuation of the liquid level between two nozzles and the directional fluxion of the solder.