Electronics Forum | Fri Aug 27 13:07:44 EDT 2004 | C Lampron
Hello, I believe that the area's of concern are primarily component related. Some component are rated for a temp (usually 260 degrees max) for some length of time. Tant Caps come to mind as being heat sensitive. The other concern would be the inerme
Electronics Forum | Thu Aug 26 13:31:05 EDT 2004 | Dreamsniper
Hi, I always caught our touch-up operators cleaning touched up boards improperly. Either by just wiping with lint free clothe the solder joints of the components after touch up or by just going behind the aqeuous cleaner and scooping some water then
Electronics Forum | Fri Sep 10 17:32:59 EDT 2004 | Yngwie
We have recently faced lifted lead problem that happened on our 20 mil pitch QFP. We have infact pushed it back to the incoming quality, but still I have a few questions to bring up : 1) what is the typical coplanarity tolerance that ICs' manufactur
Electronics Forum | Tue Sep 14 13:54:13 EDT 2004 | paul_boxboro
I'm with Chris' approach as a first effort. If you don't have any luck, consider using a high (reflow)temp solder paste for the first pass reflow, and your standard solder paste for the second pass refow. Years ago I had a similiar challenge with an
Electronics Forum | Wed Sep 15 17:50:24 EDT 2004 | GS
Hi Simon, do not forget BGA have more surface contact ( qty off balls) then a same size of QFP. I mean, theoretically unless the BGA is very heavy, it is more simple to solder mirrored PBGA then try to have QFP on bottom side to be soldered. Are ple
Electronics Forum | Wed Sep 15 11:33:12 EDT 2004 | sue ph
We are building seven different assemblies that have flex circuitry that go off in four different directions within the panel. The panels are square to facilitate flow through smt & wave solder and depanilized in solder touchup. Currently, we are usi
Electronics Forum | Thu Sep 23 13:14:22 EDT 2004 | Bob R.
We're just getting started in lead free, but the solder balling and poor wetting sounds like what we saw in some early experiments where we were investigating whether we needed nitrogen. Without nitrogen inerting we got just the kind of things you'v
Electronics Forum | Thu Sep 23 14:58:50 EDT 2004 | C Lampron
EMS-Engineer, Lead free alloys have a very low wetting creep. You probably will not ever get the same type of weting with a LF as opposed to SN 63/37. The question is if it is acceptable. Lead free solder joints cannot be inspected to the same crite
Electronics Forum | Wed Sep 29 06:20:14 EDT 2004 | Peppe
FengAng, I'm involved in similar activities on telecom products and we use as reference: MIL-STD-883E, JESD22, IEC-749. We have 2 climatic chamber to arrange a wide range of test, depending on customer use and/or specs. Based on that experience, we p
Electronics Forum | Thu Oct 07 12:14:14 EDT 2004 | bschreiber
The pre-solder cleaning of misprinted PCBs can be a completely different experience from a post-solder application. While the paper that DaveF references is excellent, you may want to read the paper by Richard S. Clouthier, "SMT Stencil Cleaning: A
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