Peter,
Have you checked PTH in your boards for barrel plating quality?. Many times blowholes are
caused by out gassing from the laminate through plating voids. A micro section of PTH showing
blowholes will be very helpful.

PL wrote:

> Hello,
>
> I would like to ask your input on trouble shooting a wave soldering
> process that I've encountered producing blow holes on the PCA. The blow
> holes were seen at random locations, mostly on small and light caps. The
> boards were manufactured in recent weeks. Some board warppage was
> noticed after the wave.
>
> Things I tried:
> - Boards from a different manufactured date, no effect
> - Turned on turbulence wave. It reduced but didn't completely eliminate
> the defect
> - used stiffener on board edge to reduce board sagging
> - used dummy weights on top of parts seen having defect to minimize
> "dancing" during wave
>
> How critical is the component lead-to-hole ratio as far as its impact on
> solder joint quality?
> Could anyone explain how a blow hole can occur and possible steps taken
> to eliminate the defect?
>
> Rgds,
> Peter
>
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pratap singh
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