Electronics Forum | Tue Jul 26 08:57:23 EDT 2011 | indyc
I am trying to rework FP4531 underfill. Some of the underfill flowed to adjacent capacitor and resistor. Even though the datasheet says that it is non-reworkable, has anyone tried reworking / removing excess underfill? Any information would be help
Electronics Forum | Tue Mar 24 22:03:39 EDT 2015 | davef
Here's some notes from IPC APEX 2015: * Black underfill is Heraeus. It needs to be preheated to 180-200*C for rework. Above 200*C it changes state and becomes difficult. * Clear underfill is from an unknown Korean supplier. * People from Heraeus w
Electronics Forum | Thu Feb 26 10:33:01 EST 2015 | emeto
Take a look at articles that explain underfill process and how to remove/rework underfill: http://www.finetechusa.com/rework/applications/underfill-rework.html http://www.circuitnet.com/experts/86535.shtml
Electronics Forum | Wed Jul 26 12:39:00 EDT 2006 | spari77
we encounter some open joint on the CPU socket after rework. We tried to reflow the boards again (using BGA rework machine) and found that the contact issue was resolved. Is there any risk to perform a reflow again on the CPU Socket boards without re
Electronics Forum | Wed Mar 04 22:57:05 EST 2009 | davef
Underfill epoxies may be classified into major groups [Capillary Underfill Manufacturing Development and Characterization for 2nd Level Electronic Interconnect Processes; B Salom�n; University of Puerto Rico, Mayaguez Campus; Dec 2004]: * Capillary.
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
Electronics Forum | Mon Mar 29 13:33:05 EST 2004 | Ron W
I was wondering if anyone has attempted to develop a process for the successful removal of a BGA and its underfill. Or, is it the general industry thought process that an underfilled BGA cannot be reworked.
Electronics Forum | Tue Apr 27 15:09:48 EDT 2004 | zymet
Hello Ron, Successful removal of an underfilled BGA requires the use of a reworkable underfill, which Zymet manufactures. For more information on such products, send an inquiry to info@zymet.com. Regards, Carol
Electronics Forum | Wed Jun 07 07:53:24 EDT 2006 | RLM
This is true but even the so called reworkable underfill takes a lot of effort. We use a loctite reworkable that requires heat to soften the underfill. Once the component is removed we use acetone and a swab to scrub the pcb clean. This can be very t
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
