Electronics Forum | Thu May 07 20:28:35 EDT 2009 | davef
From our notes, the following is a series of snips from: "Copper Dissolution in Tin" LJ Turbini, PhD, adjunct faculty member, University of Toronto, Materials Science and Engineering, SMT 2/07 As the solder becomes molten, copper from the board diff
Electronics Forum | Tue Feb 01 09:21:36 EST 2005 | TomA
I looked breafly at this alloy. My concern was that I had already implemented a SAC 305 alloy at SMT. So any of my mixed technology projects would one alloy (SAC 305) on one side (topside) and a different alloy (SN100C) on the bottomside. Most articl
Electronics Forum | Wed Nov 20 09:27:28 EST 2002 | davef
There's a fair number of issues with lead and bismuth solder alloys: * Lead and bismuth alloys can form a eutectic composition of Bi52Pb32Sn16 in the grain boundaries. Melting point of the eutectic alloy is 95�C [~96�C?]. * Fillet lifting of PTH du
Electronics Forum | Mon Jul 08 08:49:51 EDT 2002 | pjc
Interesting study. It shows no-Pb alloys having a greater negative environmental impact. I wonder if the Euros are re-thinking their no-Pb regulations? I also wonder if popular opinion and politics is at the route of our EPA's no-Pb regulations and n
Electronics Forum | Tue Dec 10 20:42:43 EST 2002 | davef
Vijay, Sounds like you're not spending enough time at liquidous plus 20*C. And you need to stay there for 5 to 10 seconds. I know, I know. We have used bucketsful of WS609 over the years. See, as you say, the melting point of your solder alloy
Electronics Forum | Mon Sep 27 22:25:05 EDT 2004 | KEN
Minimal cost and low melting point??? Have you bought Indium or Bismuth based alloys lately? Tin/Silver, Tin silver coper-X you name it....there are trade-offs (cost / performance). Not all are exactly published or are suitable for all appliations
Electronics Forum | Fri Apr 21 23:17:29 EDT 2006 | SD
Well, my first thought is that you need to consider lead-free rework. Depending on the alloy, some stations may not be able to reach the correct temperature. The best stations I have seen have a prism & shows both the pads and the BGA on a single v
Electronics Forum | Mon Jun 04 10:13:48 EDT 2007 | patrickbruneel
Chris, This is probably one of the reasons medical equipment and implants are exempt from the directive. Below a quote from an article published by the medical device network. RoHS excludes medical devices (category 8) and monitoring and control i
Electronics Forum | Thu Aug 20 15:10:21 EDT 2009 | davef
Responding to your points: * The intermettalic layers [ie, Cu6Sn5, Cu3Sn] between the solder and the copper pad is the same composition with both lead free and leaded solder. The lead in solder has no impact on the intermetallic. * As you say, increa
Electronics Forum | Sun Dec 26 21:18:04 EST 2004 | tellinghuisen
Chris, We also do not allow the use of Lead-Free BGAs in a lead based process. It is actually one of the things that scares us most about converting to Pb-free. Most of the suppliers that we have talked with are planning on moving to the SAC
