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Wave Solder Balls, VOC-Free Flux, and Glossy Mask

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C.K. Flip

#44305

Wave Solder Balls, VOC-Free Flux, and Glossy Mask | 3 October, 2006

With recent implementation of VOC-Free flux in our shop, we've experienced little solder fines/balls on the above combo of VOC-Free, Water Based, and glossy to semi-glossy mask finish on PCB's.

The solder balls show up on close conductor spacings, ~25 mil pitch and less, and on through hole leads. It appears that the surface tension caused by the glossy mask doesn't want to make the solder peel back nicely.

Yes, we checked our profile, we're evaporating the water, and we played with flux deposition rates. It seems more is better with flux, since you're effectively increasing the flux activity level and hence, easing surface tension.

Anyone have a fix for this, or experience this? One possible solution for us is to switch back to IPA-based, VOC flux. Granted the solder balls don't look dangerous enough to cause a problem, but it's a nuisance when we run the glossy stuff.

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