Electronics Forum | Tue Aug 07 08:20:47 EDT 2001 | CPI
Are there other components on the board? If so, how does solder quality look on them? Are they all reflowing? Are the sections of the uBGA�s sitting on a ground plane? Sounds like un-even heating. You should attach a couple thermal couples and see h
Electronics Forum | Thu Aug 09 12:36:26 EDT 2001 | Michael Parker
Adam- Mikie here. I too am placing 2 PBGA sockets on an assembly but they aren't mirror imaged. Thanks to the SMT Gods for that one. You say you added more paste to solve for open solder. Do you have x-ray? Were the alignments perfect? Also the part
Electronics Forum | Thu Aug 23 15:45:48 EDT 2001 | slthomas
So, we've already addressed the tombstoning on these guys by adopting the mfr's (Pana.) recommendations for pad size and spacing. Problem is, we have pretty bad wetting of some of these parts. The rest of the board we use them on looks great, nice
Electronics Forum | Thu Aug 23 16:41:06 EDT 2001 | slthomas
Naw, the rest of the BOARD we use them on. Same assembly. Actually we use them on one other assembly and have the same problem. Same oven, same line, same paste, same problem. I've tried to get the production super. to move them to another line w
Electronics Forum | Thu Nov 01 05:30:06 EST 2001 | wbu
This is not about the physical laws but besides contamination, which will actually IMO cause NO WETTING, it is quite vital that the time-limit the flux is active is not exceeded during your reflow process. Depending on your paste/flux you will have a
Electronics Forum | Tue Nov 20 20:58:43 EST 2001 | davef
Very coo!!! [You have done an outstanding job of describing your situation.] I guess the via are connected to a BIG chunk of copper that affects your profile on that pad / ball. At the same time, run a profile each on a: * Void pad * Nonvoid pad
Electronics Forum | Mon Dec 24 01:43:34 EST 2001 | sanmatech
Recently started running flex board with tin lead connectors. The problem being that when we receive the parts incoming connectors are all bright and shiny. Now after going thru the heller we encountered cold solder. At this time peak temp was at 186
Electronics Forum | Thu Jan 24 09:53:56 EST 2002 | davef
You didn�t tell us about your solder, wave temperature profile, or the distribution of the problem. So, let�s assume the solder is near eutectic and the problem is wide spread. Wolfgang makes good points. So, let's talk a different tact. When we
Electronics Forum | Thu Jan 31 07:02:00 EST 2002 | martino
The whole process counldn't be easier. The sales reps' try to turn the whole thing into some crazy black art-its not. The stencil supplier will have their own standard 'glue dot' configurations, and 9 times out of 10 these are more than adequate. As
Electronics Forum | Fri Feb 01 10:19:22 EST 2002 | cyber_wolf
Whoa! I beg to differ my friend. The cure profile is VERY critical in Adhesive curing, especially if your are screen printing. When you screen print adhesive you are leaving it exposed to the atmosphere for a period of time. SMT adhesive by nature i
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