Electronics Forum | Tue Dec 14 10:36:42 EST 1999 | Paul Peterson
I recently encountered reflow soldering defects on a pair diode package, the smd pad had a green contamination, I'm convinced that this is not oxidation. The no-solder condition appears to be caused by a sloppy soldermask process, although over the y
Electronics Forum | Wed Jan 16 15:22:29 EST 2002 | Terry Burnette
In his book titled "Manufacturing Techniques for Surface Mount Assemblies" author R.J. Klein Wassink describes the relationship between solder land dimensions, component lead coplanarity, board warpage, solder volumes, and solder paste flux wetting b
Electronics Forum | Tue Dec 14 11:08:19 EST 1999 | John Thorup
I think you're on the right track Paul. You didn't mention what type of solder mask was used but I'll presume that it was LPI (liquid photo imagable). If development of the image is incomplete some mask can remain where it is unwanted. Sometimes im
Electronics Forum | Fri Sep 29 13:51:46 EDT 2000 | C. Ortner
We work in a "low" volume high reliability house building mixed tech double sided multi layer CCA's for long lived space applications. Our present problem is inspection questioning every dimple/anomaly on every leadless part(we put passives only thr
Electronics Forum | Wed Jun 14 08:08:56 EDT 2000 | Wolfgang Busko
Hi ji tae, we had a similar problem with QFPs 0,5 pitch processed by one subcontractor. The symptoms we noticed were: - the solderjointshape and wetting looked normal - the surface had a dull gray appearance - by pushing a lead sideways with a tweez
Electronics Forum | Tue Dec 14 11:08:59 EST 1999 | Wolfgang Busko
Hi Paul, you got to find the reason first before any measures can be taken. You have to determine wether it happend somehow at your site or at the boardhouse, you can�t blame them without reason. As long as it is suspected that more of those panels
Electronics Forum | Tue Dec 14 11:13:43 EST 1999 | Chris May
Paul, I have (as many have) come across this problem due to misregistration of resist at the PCB fab. You didn't say if these boards are inexpensive double sided or costly multis. I know this shouldn't make a difference on quality but I would tend t
Electronics Forum | Thu Feb 12 12:30:16 EST 2015 | stevezeva
I remembered something from the TechNet a long time ago about heating the board with a heat gun to see if the white spots disappear. I searched the archives and found this from Bill Kenyon: Quick identification of solder mask white spots- if it is t
Electronics Forum | Thu Feb 12 08:35:22 EST 2015 | davef
Solder mask is intended to protect the traces from the soldering process. That's it. [Tried to upload a picture. It's broken.]
Electronics Forum | Mon May 09 11:29:05 EDT 2016 | jpal
I wanted to bump this up. I am having the same problems. I cannot convince folks it is a solder mask issue and not our process issue, even though it shows up after wave and wash. I can heat the boards and even send them back through the wave preheate
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