Electronics Forum | Wed Jul 17 02:32:13 EDT 2002 | computer
Hi, Anybody with a solution on solder balls on gold pad. I have tried the following a) Check cleanliness of solder paste printing area b) Clean stencils on 1 clean per 2 prints c) Use N2 on the reflow oven. Any other methods...
Electronics Forum | Wed Jul 17 08:26:14 EDT 2002 | davef
Search the fine SMTnet Archives to get started.
Electronics Forum | Thu Jul 18 02:08:37 EDT 2002 | computer
Thks for the advise.
Electronics Forum | Wed Jul 17 12:07:48 EDT 2002 | dragonslayr
DaveF is correct in directing you to the archives. This problem type has been discussed many times, it is quite common. Questions to ask yourself and provide us with answers are: It always happens or random? All assemblies or just one? solder paste
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 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 | 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 | Thu Aug 21 12:31:54 EDT 2003 | adlsmt
I have some finished boards that I have concluded have "black pad" defect. Outside of the black crap on some of the solder joints, if the boards are electrically functional, are they reliable? Any opinions would be appreciated as I dont want to throw
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
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