Electronics Forum | Fri Mar 14 04:42:24 EST 2003 | emeto
Hi, About Thombstone defects: 1.Placement accuracy-main reason 2.Soldering-should be right on pads.The print should have regular shape.The quontity of the solder on both pads on one component have to be equal. 3.Reflow: the profile have to be made v
Electronics Forum | Thu Nov 10 08:23:35 EST 2005 | arclightzero
Hello, I am currently trying to isolate internal fallout problems with very low yield substrates mixed with great yields and have recently found that we are using a Sn62/Pb36/Ag2 solder paste with full tin (no lead) components as well as Pb95/Sn5 sol
Electronics Forum | Tue May 09 18:30:35 EDT 2006 | muse95
I can understand the theory behind fewer tombstones with SAC. If people were having tombstone problems with SnPb eutectic solder, often switching to Sn62Pb36Ag2 would improve it, because with the addition of some silver, a small plastic zone in the
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 | Sat Aug 30 12:36:05 EDT 2008 | omid_juve
we are doing many experiment on this problem 1)sn63 pb37 solder paste +normal profile 2)sn62 pb36 ag2 solder paste +normal profile 3)pb free solder paste + pb free profile 4)sn63 pb37 solder paste + pb free profile but still the problem exist so i th
Electronics Forum | Tue Nov 30 18:02:45 EST 2010 | flipit
62/36/2 is used often in thickfilm hybrid circuits where Pd/Ag conductors are used. The idea is that you saturate the joint with the 2% silver and thus help eliminate the leaching of the silver from the hybrid circuit pads or the component. We mix
Electronics Forum | Mon Apr 01 17:20:45 EDT 2013 | davef
In thinking about troubleshooting tombstoning {TS} defects, seek balance: * Pads the same size * Same amount of paste on each pad * Component placed with the same amount of contact on each pad * Heating the same on each pad, no via connection to a gr
Electronics Forum | Thu Sep 16 20:55:35 EDT 1999 | Dave F
| | We have some SMT components with gold plated leads. They're actually LCC led packages. A good solder alloy to use would be Indium / Lead to reduce tin dissolution into the gold and avoid the resultant brittle intermetallic compound. However, a re
Electronics Forum | Mon Apr 19 02:45:31 EDT 1999 | Brian Sloth Bentzen
| | We process both tin/lead plated boards and gold plated boards in our surface mount group. I have used Sn62/Pb36/Ag2 solder paste on all gold plated boards to help prevent gold scavaging. To reduce the amount of different solder pastes we have t
Electronics Forum | Thu Jul 01 20:56:57 EDT 1999 | Dave F
| | | | | Could somebody tell me what means Leaching, ie: "Leaching of terminal end face exposing the ceramic"? | | | | | | | | | Roberto: Leaching, according to the SMTnet Library of Terms: | | | | | | | | Leaching. Dissolution of a metal coating
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