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Yuen

#14161

N2 wavesolder machine | 21 September, 1998

How can I solve the small solder ball in the N2 W/S ? The Oxygen level is 10000~20000ppm & no-clean flux.

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Chyrs

#14162

Re: N2 wavesolder machine | 22 September, 1998

| How can I solve the small solder ball in the N2 W/S ? | The Oxygen level is 10000~20000ppm & no-clean flux. Yuen, Sorry I an't got an answer, just more questions. 1-2% O2 in your wave solder - are you running membrane generated nitrogen? I don't think that's the cause of your solderballs. Is your no-clean flux VOC-free? Could be you're not driving all the water off in the preheat. Do you see balls around your wave nozzles? If you don't, then it's probably not your preheat, either. The biggest cause of solderballs in my experience is the flux-soldermask interaction. Glossy mask has a much larger propensity for balling than matte. Because the finish is smoother, it's harder to break the surface tension between the mask & the solder, resulting in more balls. Are you using glossy mask? THe flux manufacturers add agents to break the tension and reduce the incidence of balling. Unfortunately, these agents can often leave residues, which are undesirable as well. What kind of flux are you using? I just finished evaluating six different VOC-formulas for my N2 wave, and some definietly produced more balls than others, particularly on glossy mask. Others produced more residues, and others were less agressive on coppper-Entek, etc. Could be that you just need to try a different flux. Well, if you answer my five or six questions, I may be able to answer your one! Chrys

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