Electronics Forum | Fri Mar 07 03:37:26 EST 2003 | emeto
Hi Ygwie, My experience shows there is not unique answer.Actually it depends on design,printing reflow or wave.It might be top side with lesser cmps.Top side might have fine pitch or BGA or CSP,LLGA ....,so you have better planarity when the PCB is b
Electronics Forum | Tue Mar 11 10:13:15 EST 2003 | genny
Some people have said that for smaller components like 0402, a 2% silver paste (62/36/2)has helped reduce the tombstones. The reasoning is that this paste has a longer plastic zone compared to a true eutectic solder, and if there is any uneven heati
Electronics Forum | Tue Mar 11 11:22:38 EST 2003 | slthomas
Is a water-soluble flux based paste an option for the bottom side? Then you could wash the residues from the board before wave. That's the only way we've tried that process. The difficulty we had was with some disturbed joints, apparently from s
Electronics Forum | Wed Apr 02 12:50:01 EST 2003 | rdr
Does anyone know of any standards that deal with the physical location of BGAs on a PCBA? I am looking for something that states to not put BGAs in the center Axis of assemblies for bow and twist reasons. We have always informed customers to locate
Electronics Forum | Wed Apr 09 10:17:28 EDT 2003 | ksfacinelli
http://picturecenter.kodak.com/share?invite=ZExr4tzrmmYeI5Uozhlo Here is a link to the pictures. This is a HASL board with ws-609 paste. Lead parts look good but would like to see a shinner joint in the BGA area. Thermal profile looks good 150-15
Electronics Forum | Wed Apr 16 08:43:00 EDT 2003 | davef
Given that the LED work properly after being touched-up and that you don't have problems with other components, you may not be wetting the LED termination solderability protection during your normal reflow. Use a profiler to check the temperature on
Electronics Forum | Mon Apr 21 09:01:38 EDT 2003 | russ
Wave solder - Initially high cost but after that it is relatively cheap. Selective soldering with a solder pot such as the Air-Vac PCBRM models - Much lower cost than wave but if you get the right nozzles it is a great process. Solder preforms - s
Electronics Forum | Wed May 07 09:02:17 EDT 2003 | Kris
Hi SnAg is a binary alloy and does not have the same effect as a ternary SnAgCu alloy as far the pasty range is concerned. But then paste only can do so much. The best way to do it is to have proper pad design, controlled placement and reflow. I w
Electronics Forum | Tue Jun 03 21:50:57 EDT 2003 | yukim
A question regarding the rampup slop: as we cannot make the preheat time long enough due to our reflow oven limits, a Loctite technician suggested we increase the rampup slope, between the initial point (25C) and 80C, to 4C/sec, as between these temp
Electronics Forum | Thu May 08 10:16:17 EDT 2003 | davef
Observations are: * Center most lead of the fuse on the top right of the assembly looks like it has excellent solder flow, but this is PTH. From the amount of solder, it must have been wave or hand soldered. * Center most lead of the fuse on the bot
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