Electronics Forum | Tue Aug 24 15:05:39 EDT 2004 | Dreamsniper
There is danger in doing this based on theory. Chances of the solder joints becoming cold or having poor wetting due to the fact that during the first run all the flux vehicles had evaporated and with the second run they're no longer present to help
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 | Wed Nov 17 08:27:35 EST 2004 | Steve
No-Clean has less activators, your profiling Does change. Look at the data sheet supplied by the solder manufacturer. Then tweak the profile based on your equipment, board type, size etc. Don't burn off the activators too quickly. Also keep your chem
Electronics Forum | Tue Dec 14 07:32:57 EST 2004 | davef
On contaminated assemblies: While you isolated part of your dendritic growth to contaminated boards, could it be that you have a similar problem with other components, rather than your flux? Is this flux new? Have you had similar problems with thi
Electronics Forum | Mon Jun 20 21:54:38 EDT 2005 | darby
Contact your paste supplier and see what they say. My information on SAC 305 FROM MY SUPPLIER was - "The cool down rate is not as critical for Pb-free solder joints, as it was for SnPb. The grain sizes do not differ is size in the Pb-free bulk solde
Electronics Forum | Wed Jun 29 17:38:16 EDT 2005 | GS
Several years ago, we had almost same pbm, best results have been obtained by using water soluble paste (those time the old AM1208). Any way, to get a good toe meniscus is not so easy. Talking about CTE, keep in consideration the internal die of TSO
Electronics Forum | Thu Mar 30 09:32:54 EST 2006 | russ
Not arguing dan, but are you positive that they are not copper? anyway, what is happening is as the parts sucks down onto the board from reflow the extra paste is notnecessarily sqeezed out but it has no place to go. So it will form this ball on th
Electronics Forum | Mon May 01 22:55:02 EDT 2006 | KEN
....am I reading this correctly? "Screen Printing" or "Stencil Printing" Screen = agree = off-contact.....it's fuzzy going back into the memory banks to the early 90's. Screen mesh and emulsion will stretch to produce the gasket affect while snapp
Electronics Forum | Thu May 18 11:27:36 EDT 2006 | patrickbruneel
I'm not on the production floor on a daily basis like the other guys here but here's my 2 cents: With a Ni/Au plating the inter-metallic that needs to be formed is Ni/Sn. Ni/Sn inter-metallic requires higher peak assembly temperature and a longer dwe
Electronics Forum | Wed Aug 16 13:29:51 EDT 2006 | SWAG
Is 811 lead paste? If so, it seems to me that your oven settings are getting into soak awful fast in zone 2 and your peak is way high. Unless you are doing a thick board or something like that, those oven settings seem aggressive and might result i
