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SOLDER BALLS / SELECTIVE SOLDER

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#66534

SOLDER BALLS / SELECTIVE SOLDER | 6 June, 2012

I am experiencing many solder balls when using my selective solder machine when leads are fairly close together. Using a no-clean flux (3.4% solids). I have changed the volume of flux with no change in amount of solder balls.

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#66538

SOLDER BALLS / SELECTIVE SOLDER | 6 June, 2012

Higher temperatures are the primary reason that there are more solder balls with selective soldering than in wave soldering. Possible causes are: * Solder mask type is the most important factor ... Solder resists becomes stickier at higher temperatures. * One flux may be more prone to produce solder balls than another. * Too much flux * N2 adjustment is too high * Preheat is too low

Here is a link to a recent thread on this topic here on SMTnet http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Message_ID=66094

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