Electronics Forum | Wed Nov 14 03:26:38 EST 2012 | spopov
Ryan, in some cases we use 2 pastes with different melting temperature (LF SAC and PbSn)for complex boards with components on two sides. And we want to try to replace LF SAC with low melting paste.
Electronics Forum | Fri Mar 28 10:21:16 EDT 2014 | davef
With heat, most underfills soften just before the solder melts. So, keep poking the underfill until you see it soften. Then, wait just the correct amount of time until the solder melts and quickly snap or torque the part from the board. BR davef
Electronics Forum | Thu Sep 15 10:49:58 EDT 2016 | emeto
Remove,clean, re-ball(or use new part), reflow. Body of the part is designed to withstand heat that is higher than the melting point of the balls alloy.
Electronics Forum | Thu Sep 15 16:07:19 EDT 2016 | davef
In electronic manufacture, it's never good when "oozing" is part of the conversation. "Bridging" that's bad too. "Melting" sometimes good, sometimes bad. Got pix? How about some nice color pictures?
Electronics Forum | Mon Sep 13 17:39:02 EDT 2021 | duchoang
Agree. The big pad and part nearby made the paste on two ends of cap melted unevenly.Deposit more paste on the tombstone-ed pad will make it easier to melt. Nothing wrong with profile if everything else is OK. BTW, how to measure temperature on two e
Electronics Forum | Tue Jul 24 03:26:45 EDT 2001 | winnifred
Dr. Lee, For lead-free wave soldering, we are recommended to use SnCu0.7, why not 0.8 or more ?? Since SnCu0.7 has eutectic melting point at 227 deg C, does it mean with more Cu or less Cu, the melting point will be higher ?? Also, in lead solderin
Electronics Forum | Fri Dec 02 08:52:05 EST 2005 | pavel_murtishev
Good evening, I�ve just solved very similar soldering issue. In my case the problem was with 0603 chips. Solder joint had same appearance. I suspected that solder do not melted and increased TAL and peak temperature. No result. Next thing I tried to
Electronics Forum | Wed Feb 07 16:20:46 EST 2007 | davef
Bismuth is a low-melting metal with poor mechanical properties; if you melt the bismuth wire into a standard tin-lead solder joint, then the bismuth alloys with the solder, and forms a material that will crumble if you scrape it with your fingernail.
Electronics Forum | Mon Mar 26 07:38:26 EDT 2007 | davef
The temperature that will melt solder holding top side SMT components during wave soldering depends on the alloy of that solder. So, for example, you'd expect: * Near eutectic SnPb solder to melt around 215*C. * LF to melt around 240*C. It's common
Electronics Forum | Mon Sep 28 13:03:43 EDT 2015 | dyoungquist
The melting point of the solder itself does not change when you have underfill. If the underfill conducts heat better than air, it will take less heat (and/or less time) from your rework station to get the solder up to the melting point. That makes
