Electronics Forum | Thu Mar 30 09:32:54 EST 2006 | russ
Not arguing dan, but are you positive that they are not copper? anyway, what is happening is as the parts sucks down onto the board from reflow the extra paste is notnecessarily sqeezed out but it has no place to go. So it will form this ball on th
Electronics Forum | Mon Sep 20 11:21:48 EDT 2010 | tony1
I have this NiPdAu small QFN packge sizes less than 2x2. I tried to do solderability Dip And Look test and there's always some units no wet on either ground pad and small I/O. Can someone help to explain why is this so difficult to set on this surfac
Electronics Forum | Thu Aug 10 10:52:11 EDT 2017 | ttheis
We are just using a stereo microscope at this time. When we first started out with these parts a year ago they filleted very well but with no apparent change they began having problems. While the boards do work, we are concerned about the long term r
Electronics Forum | Tue Apr 27 05:10:34 EDT 1999 | Earl Moon
| Which is the preferred method for soldering a bga, adding solder paste or not? Solderpaste manufacturers say to add solder while the rework station manufacturer's say it's not necessary. | Paste is preferred by not necessary. Our studies, conduct
Electronics Forum | Thu Nov 21 05:44:07 EST 2002 | kcorrin
We produce several boards with reflowed components on top and bottom. We are finding the solder has wetted to the leads but did not flow completely to the end of the lands. Several factors/causes?: 1) Board warping but paste deposits look good. 2) Mo
Electronics Forum | Wed Apr 06 11:10:47 EDT 2005 | smt_rookie
We process a double-side reflow board (10 ups). Chips and IC's on the bottom side while chips, IC's plus thru-hole connectors and IC sockets on top side (bottom side first then top side reflow). In the past, we were not encountering any soldering pro
Electronics Forum | Fri Dec 16 08:00:26 EST 2005 | jax
What you are most likely dealing with: Insufficient Pure Sn layer ( multiple causes ) Because elevated temperatures accelerate the diffusion process, the thickness of the Pure Sn layer will reduce during every thermal cycle... ( bakeing PCBs, S
Electronics Forum | Wed Jul 02 12:42:58 EDT 2003 | slthomas
Not sure how else to describe this. We've received some boards (1/2" x 3.5" x .0325" board built on panels of 24) with numerous resistors showing separation of the solder from the metallization at the top of the joint. There are 26 0805's on the bo
Electronics Forum | Tue Sep 28 17:56:02 EDT 2004 | Vee Sar
Adam, I would first check hole to lead sizes on the components that you are having hole fill issues with to see that the spacing is withing spec. Second, check for oxides on lead tips, and contaminated leads that cause poor wetting and insufficient
Electronics Forum | Fri May 25 13:38:15 EDT 2007 | mfgengr
TAL Too Long - dull solder joints, dewetting. TAL Too Short - cold solder, insufficient wetting. You want TAL to be as short as possible (but not lower than 30 seconds), but long enough for every solder joint to be above TAL for at least 30 seconds.
