请帮忙解决：锡镀层在再流焊过程后的问题？

huolizhu

ituation: After 260 oC reflow three times, each time 10 second, pure tin electrolytic surface will have discoloration. Why? Do you have any

suggestion to prevent this occur? 经过260度再流焊三次，每次10秒，纯的锡电解镀层表面会出现退色（色斑），为什么？怎么阻止它发生？

Situation: After reflow process, tin/lead surface will easily occur dewetting. What is the root cause of it? Why? How do you start to

investigate it? Do you have any suggestion to minimize this? 经过再流焊后，锡/铅表面很容易去湿。它的根本原应是什么？为什么？怎样分析调查？怎么尽可能减小？

How can you reduce whiskers appearing on the pure tin electrolytic surface? What is the reason appearing whiskers? Please state 怎么减少出现在纯的锡电解镀层表面的锡须？出现锡须的原因是什么？请解析

During CVS analysis, the analysis results often show unstable and fluctuation. What is the problem in here? How can we solve this problem.

Please state suggestion 在CVS分析中，分析结果经常出现不稳定和起伏，原因？怎么解决？

fyyl88

过回焊炉的次数应该不会超过二次啊，本身锡就是焊接次数不能超过二次，否侧很容易虚焊的。过三次回焊锡面肯定会有变色的，可改为金板就没有了。

锡表面的锡须一是由于电流密度过大造成的，还有就是酸含量过高所造成的，同时，不排除有槽液内有锡渣的可能性，先分析药水，可适当降低酸的含量，或隆低电流密度，每星期做活性碳处理一次

所说的起伏是什么样子的？有图片吗？这样也难理解！

[em01]