Electronics Forum | Fri Mar 18 14:22:37 EDT 2011 | bradbriggs
We recently ran into a situation where a SMT header with tin plated tails would not wet properly during reflow. Someone told us that tin plating has a shelf life and needs to be re-tinned after a length of time. I have not heard of that before. Do
Electronics Forum | Tue May 10 15:44:24 EDT 2011 | davef
From your graph, we just don't see the the relationship between failures and relative humidity. Questions are: * What is the correlation between failures and RH? [We'd bet that the correlation between failures/RH and failures/temperature are 'similar
Electronics Forum | Tue May 31 22:40:24 EDT 2011 | bejrananda
HI All, Please kindly advice me, I have project that it has DPAK part (MPN:SUD25N15-52 E3 Plating:100% Sn matte)which locate on bottom side (1st reflow), Good wetting for 1st reflow.. but .. when I run Top side (2nd reflow).I found that this D
Electronics Forum | Thu Jun 02 10:54:12 EDT 2011 | davef
Al: We agree with AVFOM. You have a different problem than solder paste mesh selection. Most often, tombstoning occurs when the wetting forces on the two pads are unequal. Examples of things that can cause this are: * Pads are different * Board pad
Electronics Forum | Fri Jun 24 09:32:53 EDT 2011 | kahrpr
Looking at the appearance of pads and solder joint is pretty subjective. Especially lead free people are all over the map on the physical appearance of pads and joints. The true test is solderabilty testing, weather it’s just looking for good wetti
Electronics Forum | Thu Aug 25 21:26:27 EDT 2011 | leadthree
Solderability could be an issue. We usually buy the IC and stock it for up to 9 month. This time the ICs was from a broker and the datecode was not the latest. This said, we use already a solder paste that contains watersoluble flux, which is suppos
Electronics Forum | Mon Nov 21 10:51:12 EST 2011 | scottp
I've never seen a good article with a definitive explanation - just speculation that the increased wetting forces due to nitrogen result in increased tombstones. My own experience is that nitrogen is a very minor contributor to tombstones and can pr
Electronics Forum | Mon Mar 19 22:09:38 EDT 2012 | davef
J-STD-003B prescribes test methods, defect definitions and illustrations for assessing the solderability of printed board surface conductors, attachment lands, and plated-through holes utilizing either tin/lead or lead-free solders. This standard is
Electronics Forum | Thu Apr 05 11:48:25 EDT 2012 | pbarton
Are you running individual point soldering on each component lead, of are you drawing lines with the solder fountain to increase the speed of the process? Could be that if you are drawing lines, coupled with the very low flux levels you say you are
Electronics Forum | Mon Apr 09 20:55:46 EDT 2012 | action_101
I forgot to add that we are using a 3 mil stencil. It seems like to me that may be there isn't enough flux left when we reach liquidous?? About half of the solder spheres do melt and wet on each pad, but the top half of each solder joint is just the
