Electronics Forum | Wed Mar 11 10:58:58 EST 1998 | Earl Moon
| | What does the term "poor wetting" mean as a defect code ? "Poor" should mean unacceptable when surface (component or PCB solder termination areas) wetting does not provide acceptable solder joints. Unacceptable wetting of PCB solder termination
Electronics Forum | Tue Apr 11 16:42:56 EDT 2000 | Chad Notebaert
I�m thinking �Poor intermatallic� It could be a few things. Lets start at the beginning. -Is your paste a 63/37 mixture? -Have you monitored you screen printing, Verify Solder deposition, Are you getting enough paste? -You say the solder looks like i
Electronics Forum | Tue Apr 11 20:26:16 EDT 2000 | Dave F
Jeremy: Parts assembler make leads of either Alloy 42 (Invar, whatever) or copper. The solderability of these leads are protected with eutectic or non-eutectic tin/lead solder, palladium or some palladium alloy, or gold. Cuppla things to consider:
Electronics Forum | Thu Sep 07 03:47:07 EDT 2006 | vicknesh28
I have been getting non wets on fine pitch QFP packages on random leads during reflow process. I noticed that every time there is some flux residue left between the non-wet lead and the solder pad. No residue was not observed on the rest of the good
Electronics Forum | Tue Feb 09 16:53:06 EST 2021 | SMTA-64387083
The size of the pad changes among the two. A solder mask defined pad will always be larger than a copper defined by your mask expansion setting. This will affect paste volume, if your standard paste aperture is designed for copper defined pads you m
Electronics Forum | Thu Sep 07 07:41:06 EDT 2006 | Bubba
Check for coplaner leads if this just exists at reflow process, i.e. look at part before oven, turn on 3D at placement machine. If you see after wave solder, the wave could cause coplanarity issues on top as well if you are going slow enough to refl
Electronics Forum | Thu Dec 01 14:42:57 EST 2005 | Amol Kane
my first thought was that too, but all the other components on tha board have reflowed properly. I have tow test boards, one with Imm Sn and other with Imm AG. on both these boards only the QFP has this solder phenemenon
Electronics Forum | Fri Apr 29 14:16:16 EDT 2011 | ppcbs
Below is the long explanation. This defect is most commonly found with BGA components, but can arrise with all components. I see it happening more now with lead free boards that are being assembled with a no clean flux. Best short term remedy is t
Electronics Forum | Thu Dec 01 14:24:25 EST 2005 | Amol Kane
Hi, I am having a SAC 305 solder paste with water soluble flux wetting issue. during reflow, the solder melts, but doesnt flow. the reflow profile was developed by the solder company person (Kester). the board is a test assembly to validate our LF pr
Electronics Forum | Tue Jul 30 08:37:39 EDT 2002 | davef
When you talk about 'poor wetting', 'dewett', 'no wets', etc.; are you seeing solder pulling back or away from the pad? Please describe the condition. Dewetting. The condition in the solder joint in which the liquid solder has not adhered intimate
