Electronics Forum | Wed Oct 27 19:50:59 EDT 1999 | chris
Hi What is the possible cause of non-wetting of solder paste to the gold land pad. What we observed in the surface of the non-wet pad is an organic FM, and using FTIR we found out that it is a flux. It is possible that the cause of non-wetting is
Electronics Forum | Thu Nov 04 21:36:36 EST 1999 | chris
Hi John, Thanks to your reply, just one question is it possible that the solder paste ( flux material )applied to the pads cause the non-wet. regards Chris
Electronics Forum | Fri Nov 05 10:01:04 EST 1999 | Dave F
Chris: You can have more than "one question!!!" Anyhow, yes crappy solder paste can cause non-wetting, but before you go there understand why the paste is wetting some surfaces, but not others. Ta Dave F
Electronics Forum | Thu Oct 28 09:25:35 EDT 1999 | Dave F
Chris: Typical non-wetting causes are: * Poorly controlled soldering process * Incorrect material * Surface contamination * Insufficient preheat * Misapplied solder mask * Shadowing Without intending to insult you, all of the causes of non-w
Electronics Forum | Thu Oct 28 20:45:38 EDT 1999 | chris
Hi Dave, We suspect that the organic FM causes the non-wetting problem. FTIR analysis confirm that the FM is a flux residue. Dave we only used FTIR to detect organic contaminants, we also used SEM/EDX to determined the elemental composition of the
Electronics Forum | Fri Oct 29 09:36:42 EDT 1999 | Dave F
Chris: Thanks. SMTnet has a "Library." Buried deep within it is a listing of terms. The following is from that listing: Shadowing. When a component blocks the heat or solder wave flow from certain areas of the printed circuit board, resulting in
Electronics Forum | Fri Oct 29 10:02:28 EDT 1999 | John Thorup
Chris A lot of people have reported sudden, fab lot related problems with Ni/Au pads. These are usually characterized by a discoloration of the gold and called cheerful names like "black pad disease". This can be a process problem at your fab house
Electronics Forum | Tue Dec 08 15:19:42 EST 2015 | proceng1
Apply the correct amount of paste for the pad size should work ok, as long as the part starts out in the paste. If you have a reduced aperture and the leg doesn't quite touch any paste could result in non-wetting or insufficient solder issues. I gu
Electronics Forum | Wed Sep 10 04:23:42 EDT 2008 | gregoryyork
Wheres the Gold layer on the non wetted part of the pad
Electronics Forum | Fri May 12 19:42:05 EDT 2023 | emeto
Have you tried cleaning these spots with anything?
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