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 | 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 14:59:05 EDT 2000 | Glenn Robertson
Jeremy - What's the process flow on these modules? Are they wave soldered? What is the board finish (ENG, HASL, etc.)? Glenn Robertson
Electronics Forum | Mon Apr 17 19:30:27 EDT 2000 | Boca
All of the above is good stuff. To add, I have seen this several times if the assembly is wavesoldered. Heat from the wave can partially reflow the top side SM solder joints and weaken them. To test, check joint strength before wave and then after
Electronics Forum | Sat Nov 10 23:46:36 EST 2007 | mika
BTW, The surrounded QFN fine pitch terminals should have the normal aperture reduction of 7 % in case of RoHS Senju solder paste. This works for our Telecom customer. The vias in the ground pad will be somewhat filled with solder and makes it diffi
Electronics Forum | Mon Nov 12 09:22:41 EST 2007 | devajj
BTW, The surrounded QFN fine pitch terminals > should have the normal aperture reduction of 7 % > in case of RoHS Senju solder paste. This works > for our Telecom customer. > > The vias in the > ground pad will be somewhat filled with solder >
Electronics Forum | Mon Jan 12 08:59:57 EST 2004 | Paul F
I may have a similar problem at the moment with a QFP-68. Do the unsoldered leads leave a perfectly formed footprint in the reflowed solder? Do you usually find this issue occurring towards the corners of the QFP rather than in the middle of a row?
Electronics Forum | Thu Jan 15 15:08:43 EST 2004 | mrmaint
Are your qfp's being stored properly. I have seen this in the past and it turned out to be a moisture issue. We saw most of the problems on the corners. The component would swell during the reflow process thus lifting the corners. After baking the re
Electronics Forum | Wed Sep 05 08:10:45 EDT 2007 | davef
Questions are: * Do not judge the quality of a solder connection by the shineyness or color of the solder connection. Do you have smooth and unform flow, no pitting, and good wetting to the lead and the pad? * What is the temperature of the leads of
Electronics Forum | Sat Sep 15 01:42:36 EDT 2007 | mun4o
Hi, I attach the termocouples with high temperature solder wire, at the QFP pins.Other thermocople I attach at package with high temperature tape.
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