Electronics Forum | Thu Nov 03 07:22:16 EST 2005 | davef
arnold: I did not say that Sn100 dissolved copper faster. The graph of dissolution rates [from the link above] shows that Sn100 dissolves copper slower than many of the other solders.
Electronics Forum | Wed Nov 02 01:30:12 EST 2005 | fctassembly
Hello Arnold, Yes, by definition of joint formation, copper will dissolve in lead free solder in order to form the connecting intermetallic layer. There is a distinct difference in the copper dissolution rates of the major alloys being considered wi
Electronics Forum | Tue Jul 07 08:42:49 EDT 2009 | ewchong
kpm, you are probably right. under magnification those two pads show some exposed copper which means that they were contaminated or had insufficient solder paste before reflow.
Electronics Forum | Thu Jul 02 13:10:22 EDT 2009 | kpm135
On first glance it looks like those particular pads were not attached to any traces. If I had to guess I would say that your rework profile got hot enough to melt away the glue holding the pads to the board and they came away with your part when you
Electronics Forum | Fri May 17 15:50:17 EDT 2002 | davef
Now that�s a switch. Most are moving or properly have moved in the polar opposite direction. Dano, has someone been drilling your teeth lately? We use water washable flux to: * Remove solder balls. [Or put another way, we don�t have to screw-down
Electronics Forum | Thu Jan 10 11:22:48 EST 2013 | pbarton
Looks to me like under etching of the underlying copper and the gold is just plated to all of the exposed copper surface. Is this characteristic the same on all solderable pads? You will not be able to remove this gold.
Electronics Forum | Wed Apr 14 20:24:48 EDT 2004 | Ken
What do you mean the solder must "survive" 260C? What is your target temperature? Is it dictated by a component, the substrate or the solder alloy? Do you require a eutectic alloy? If not, the selection of alloys grows. (these are from memory...n
Electronics Forum | Sat Mar 04 03:48:26 EST 2023 | researchmfg
We had sucessful removed the solder mask by laser machine and got good result and quality without damage the copper layer. You may refer to youtube here by https://youtu.be/cQHaE3_fiqw
Electronics Forum | Tue Nov 04 12:58:17 EST 2008 | smt123
I have to agree with Patrick here. This image appears to show a board that is NOT HASL as there is what appears to be a copper pad in the upper portion of the image. But then again the arrow tip appears to be white and I woudl expect that to be red s
Electronics Forum | Thu Sep 11 02:54:27 EDT 2008 | cobar
The 2 % is Ag.It is added to prevent leaching silver from the end caps of components.This alloy like 63/37 is eutectic and has a reflow temp of 179�C whereas 63/37 is 183�C.
.gif)
winsouce.jpg)
