Electronics Forum | Thu Apr 11 20:35:22 EDT 2002 | davef
Messy. Messy. Messy. Consider gluing these components, until you control your process. It is unclear to us that a single factor drives these defects, but multiple factors that need to be tuned to work well together. PAD DIMENSIONS * Some SM-782 pa
Electronics Forum | Fri Mar 06 10:46:35 EST 2009 | davef
First, we agree with Loco that your QFP is nonwetting, rather than dewetting. Your sceen-shots look like ol' timey SnPb paste recipes. Turn-up the heaterometer dial. Second, on nitrogen: * We kinda think your O2 needs to be around 100ppm with 99.99%
Electronics Forum | Sun May 04 22:10:20 EDT 2003 | Thomas
Did u ever try a anti-tombstone solder paste to try to eliminate this problem ??
Electronics Forum | Fri May 30 11:23:10 EDT 2003 | dsuraski
AIM has an article that includes anti-tombstoning solder paste information. It's called "Reducing The Tombstoning of Small Discrete Components" and is located at http://www.aimsolder.com/technical_articles.cfm#14 Or I can send a copy to anyone inte
Electronics Forum | Mon May 05 11:35:00 EDT 2003 | Grant
Hi, This is an interesting point. I use Koki paste from Japan, and it's wonderful, however what properties of solder paste would make it "anti tombstone" paste? How does led free effect tomb-stoning? That would be interesting to know. We might go
Electronics Forum | Thu Aug 28 20:24:30 EDT 2003 | yukim
Hi, do you know how much the problem can be reduced by using anti-tombstoning solder paste? I tried two different lots using same solder paste (containing Ag). With one we did not see any improvement and with the other one, a lot. So, I am not quite
Electronics Forum | Thu Apr 10 07:47:47 EDT 2008 | ck_the_flip
Stencil design and pad layout are key. Too far apart - bad. If your pad geometry is correct, try the inverted home plate. That has worked well for me in the past. That, coupled with a 5-mil stencil. With regard to solder paste, some manufacturer
Electronics Forum | Thu Jul 20 14:05:59 EDT 2000 | Mike McMonagle
With 0402 components becoming more common today outside of the telecommunications industry, our company is qualifying equipment and processes for an upcoming product incorporating 0402s. Having used 0402s in a previous position, I am planning a DOE o
Electronics Forum | Tue Sep 14 10:54:37 EDT 1999 | Scott Davies
| Can anyone out there pls enlighten me on how to solve chip tombstone defects. | I am running a board with a lot of 0603 chip. i had fine the profile and the alignment, but it still happen randomly on the board itself. Is there any other way to sol
Electronics Forum | Thu Feb 13 03:49:15 EST 2014 | jlawson
Yes all above is correct, as solder deposits get smaller and mesh T4+ , actual metal to air contact surface area increases , say in contrast to T3, add to this less flux , and flux running away from the joint, re-oxidation and what flux is left, can
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