Electronics Forum | Wed Nov 17 20:11:29 EST 2021 | dwl
is there flux on the board? are you probing a test point or a soldered pad? is the probe hitting the right spot?
Electronics Forum | Mon Sep 23 18:11:10 EDT 2002 | steveb
On an assembly reflowed in air saw the same thing: 0201's with a grainular solder joint, but 0402's and above with perfectly formed joints. Reflow profile all within acceptable tolerances. Reflowing in nitrogen solves this problem, but increases t
Electronics Forum | Fri Sep 12 09:10:23 EDT 2003 | Norm Morikawa
Around 1989 I had this probelmm with a SMT CCA that would not solder in one area consistently. I had it cross sectioned by the bare board supplier and found that under their metallurgical microscope the thickness of this HASL bare board could not be
Electronics Forum | Thu Mar 03 11:23:50 EST 2005 | Slow Ride
Generally QC is a different deptpartment than touch-up people. Most touch-up people are just general operators, so to keep their job they always see the solder joint as "not enough". Q.C. people are generally a bit better, but know they may be call
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 | Tue Aug 12 15:34:37 EDT 2008 | grics
That is very interesting... I am curious though, why wasn't a plain blind rivet used? You probably can, but personally, I would be not want a solder joint holding the frame and the pcb... Mechanical stress on solder joints often leads to not good re
Electronics Forum | Tue Sep 29 11:37:52 EDT 2015 | robl
Hi Marlyn, We use durastone pallets over a wave - so areas machined out so the solder can get to the pins but not the SMT. You can also get fancy selective solder machines, but I'm guessing that as you're asking you haven't got one. Hope that help
Electronics Forum | Thu Jun 28 09:57:50 EDT 2012 | mosborne1
blow holes and via holes are almost always caused by moisture and in PTH they could be moisture and improper drilled holes. If you are seeing solder balls next to the parts than I would say you have a reflow profile problem. Are you using any kind of
Electronics Forum | Wed Oct 04 14:18:05 EDT 2006 | C.K. the Flip
The main cause of voids is your flux out-gassing during reflow. Try a little "knee" or slight soak in your thermal profile to dry out the volatiles a bit. Typical soak ranges from 130 deg. C to 170 deg. C for around 30-90 seconds.
Electronics Forum | Wed Oct 04 16:24:48 EDT 2006 | russ
try Alpha OM5100 this is a noclean paste that we use and have done the same thing you are now, reflowing pbfree with pb paste, we run to max temp of 230C with this paste and use a straight ramp with no soak profile is about 4 mins long from ambiant
