Electronics Forum | Wed Apr 09 15:05:11 EDT 2003 | davef
This just makes my head hurt. Why do these 22 BGA with hundreds of solder connections each have "open circuit due to the lack of solder paste"? Something just doesn't sound Kosher. Tell us about: * Stencil design * Solder paste * Board design in t
Electronics Forum | Mon May 05 18:48:23 EDT 2003 | Kris
Hi, It is expected that lead-free will have reduced tomstoning. As it has a higher surface tension and does not wet as well as the tinlead paste it exibit lower tombstoning. Addiotnaly commercialy available lead-free alloys may not be true eutectic
Electronics Forum | Fri Jul 30 00:21:01 EDT 2004 | Jet
Hi, Very interesting article on tombstone issue, i'm facing tombstone issue for 0805 IDC component, i've redesign the stencil aperture and change to lead free paste, the tombstone is reducing but not fully eliminated, however there is a problem i fa
Electronics Forum | Mon May 19 02:59:04 EDT 2003 | emeto
Hi, I can give you a few steps. 1. The solder paste. Take the profile that manifacturer gives for the paste. 2. Use termocouple to measure the tempereture. Put PCB and measure the temperature in equal terms. 3. Compare your profile to manifacturers
Electronics Forum | Tue Jun 03 06:29:43 EDT 2003 | mk
Orrrrrr, you could eliminate the printing, shorting, and special surface finishes by bringing the boards in with the paste already on them. There is a process that is a much more forgiving method for applying paste called solid solder deposit. Check
Electronics Forum | Thu Jun 19 10:18:22 EDT 2003 | Dave Milk
Hi Kevin, I hope this info is timely. To qualify a component for lead free use you need to use a lead free paste. The various lead free pastes have very different wetting capabilities and temperatures required to cause them to reflow properly. Yo
Electronics Forum | Thu Jun 19 12:47:47 EDT 2003 | russ
I would believe that the connector spec is for the max temp that it can withstand while the paste is the max temp that you need to achieve. Solder balls are usually from excessive ramp rates in the oven. I would contact the connector mfg. and see wh
Electronics Forum | Wed Jul 09 13:48:03 EDT 2003 | russ
Sam, You may want to be careful with your analisys, reducing paste volume also reduces flux volume. Flux is there to promote and aid in wetting. by reducing flux you may have initiated the poor wetting yourself with the experiment. Just anothe
Electronics Forum | Wed Jul 16 21:38:27 EDT 2003 | sam
I have done a DOE on the SMT components, not the BGA, for reducing void within the solder. The result did not help in the void reduction, but confirmed that the speed of the IR oven, solder paste thickness may be the important factors for the void.
Electronics Forum | Fri Aug 22 09:41:49 EDT 2003 | davef
Mantis: Kenny reflows paste on [wave solders] all via, not just the test via, to plug the via and provide for a pressure seal between the board and the test fixture. Beyond that, since solder is softer than copper [and fills the hole better], solde
