Electronics Forum | Fri Aug 04 09:09:22 EDT 2006 | russ
Aj is right, utilize the homeplate aperture, this reduces the amount of paste actually underneath the component, Pb frees exhibit this mid ship more often than the lead, I think,it is mostly because of thre transition to noclean form water solubles
Electronics Forum | Thu Jun 21 07:21:26 EDT 2007 | chrispy1963
5 mil is perfect for 0402's. If you are printing SnPb solder use apeture reduction such as home plating the pads. However, if youre using SAC, we've found that printing the entire pad works best due to poor wetting compared to SnPb paste. Chris
Electronics Forum | Tue Mar 16 16:59:09 EDT 2010 | davef
Most often 'solder graping' refers to poor solder wetting, where the solder paste has partially melted, but has not coalesced or flowed. Sometimes this leaves the outline of the partially melted solder balls still visible, giving the appearance, to
Electronics Forum | Fri May 14 09:00:35 EDT 2010 | rafacadiz
I attached a RX picture. A lot of voids and micro balls arround the flux residue. What do you think, relow temperature reflow or OSP poor weeting.? I appreciate your comments. Thanks,
Electronics Forum | Fri Oct 11 16:25:43 EDT 2013 | scdunlap
Also coplanarity can be poor on these parts so overprinting the paste (beyond the pad perimeter) can increase volume to insure robust solder joint.
Electronics Forum | Wed Aug 09 08:46:01 EDT 2017 | stivais
I agree. Just thinking.. could it be copper plating issue as well? anyway, would be interesting to see some photos. Sounds like solder (from HASL process, wave or even poorly washed SMT solder paste) to me.
Electronics Forum | Tue Nov 26 18:35:20 EST 2019 | slthomas
It's hard to tell from the image but it looks like there isn't much room for a heel fillet. Seems like that could contribute to your voiding (or poor wetting) if there isn't enough paste volume there.
Electronics Forum | Thu Aug 08 10:25:51 EDT 2024 | carl_p
If the connection is poor you would need to consider was the solder volume correct & is the oven profile correct? Was the paste mixed correctly & within all operating windows such as exp date, time out etc etc
Electronics Forum | Tue Aug 01 08:52:53 EDT 2006 | davef
We never changed any thing after moving to imm silver. "Poor release" (paste hanging-up in the stencil holes) could have three main (or combination of) causes: 1 Equipment * Proper aperture area ratio provide better release * Laser cut release bette
Electronics Forum | Tue Sep 24 12:49:43 EDT 2002 | dragonslayr
Aperture reduction @ 5 mils thickness is your best bet. It may take several attempts to get just the right paste volume. What aperture reduction was specified to the stencil house for these specific LEDS? or was the stencil blindly produced using a
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