Electronics Forum | Fri Feb 17 11:01:47 EST 2006 | amol_kane
with lead-free solders, one would expect to find less instances of tombstoning. this is because SAC alloys are not eutectic and melt over a range of temp (usually 217-220 deg C) instead of at a single temperature. therefore the forces due to solder s
Electronics Forum | Thu Jun 22 17:47:05 EDT 2006 | davef
First, we expect voiding in imm silver to be similar to ENIG. We expect more voiding in OSP than other common solderability protection. Second, choosing a solder paste, which does not contain resins and activators that decompose at higher temperatu
Electronics Forum | Wed Sep 10 12:56:09 EDT 2003 | davef
Intermetallic compounds [IMC]: * Form during the alloying process of some metals. In soldering these are Sn, Ni, Ag, Cu, Au. * Do not accept solder. * Increase in depth in logarithmic proportion to both time and temperature. [So during the solder
Electronics Forum | Thu Feb 26 14:47:19 EST 2015 | superlen
unique mnf/mnf part number. - Be meticulous on maintaining your WO Boms. Train your employees to not circumnavigate keeping the WOBOM accurate to what they kitted/placed on the board. If you keep the one to one part number relationship above this is
Electronics Forum | Fri Jul 28 14:34:13 EDT 2000 | Gary Simbulan
Belive it or not, these boards were run through a Centech batch mode Vapor Phase machine. Single stage top side IR preheat. Vapor temp 218 C. Solder paste is an SN62 RMA.The boards were FR4 8 layer w/ solder mask, fairly conventional as might be e
Electronics Forum | Sun Mar 01 15:52:13 EST 1998 | Earl Moon
| From several months I am investigation about the VOIDS PERSENCE and his important as reliability. | One question now is : | It is possible that on the BGA components the voids are already present into the balls, before the mounting on the pcb ? | I
Electronics Forum | Thu Sep 11 16:50:18 EDT 2003 | davef
Sure it's conceivable that thin HASL can cause tombstoning. Harkening back to the ample discussion in the fine SMTnet Archives, tombstoning is caused by an imbalance in solder surface tension between the two pads of SMT component. The source of thi
Electronics Forum | Wed Aug 23 14:59:32 EDT 2006 | bill
I�ve been lurking on the forum for a while so I will take a stab at this, mainly because there is no answer I take it that you have a variety of boards being produced at the same time and are in fixtures so the conveyors don�t need to be adjusted, a
Electronics Forum | Tue Aug 28 11:12:23 EDT 2007 | grics
This is what I was thinking, but I am being beat up pretty badly by the selective solder. Ambient temperature is anywhere in the the neighborhood of 76 - 80 degrees F. I am not sure of the RH, but I wouldn't think that would be my issue... One of
Electronics Forum | Thu Mar 13 01:42:58 EDT 2008 | Sean
Thanks Real Chunks and Davef...Yours input is valuable to me. My inputs towards your question asked below: Questions are: * Why did you tell us the following? "This BGA is installed with heatsink (with hook at both side of the heat sink) manually b
