Electronics Forum | Thu Nov 24 07:41:33 EST 2011 | davef
Here's a paper from the SMTnet Newsletter http://www.smtnet.com/library/files/upload/dispelling_10_myths_about_nitrogen_reflow__andy_mackie.pdf
Electronics Forum | Mon Apr 01 10:24:29 EDT 2013 | emeto
First check the profile. I would go with linear profile and smoother increase of temperature. Usually you will get tombstones when you have too aggressive profile. My next step will be to redesign the stencil.
Electronics Forum | Mon May 27 16:17:30 EDT 2013 | nikyta
Hi Eric, you have the right reduction on the stencils apertures? Also, a very oxidized solder paste can -and will do- promote and increase both the tombstoning as well as the solder balls.
Electronics Forum | Wed Oct 01 20:09:24 EDT 2014 | isd_jwendell
No one has mentioned paste, but I have tested pastes where some do much better than others at not tombstoning parts.
Electronics Forum | Tue Dec 01 13:15:32 EST 2015 | sfeinsp
why you need to verify every day? We do it only if machine start missing a lot, and using board with banch of misalignment's, tombstones and other problems.
Electronics Forum | Fri May 06 08:47:05 EDT 2016 | davef
You're correct. This design will have a record amount of 0402 rework for tombstoning and misalignments. Suggest that the pads on each end of all components be the same size in order to balance wetting forces during reflow.
Electronics Forum | Mon May 09 09:23:45 EDT 2016 | markhoch
I agree with the previous two replies. This is a perfect design....if you're trying to create a graveyard full of tombstones.
Electronics Forum | Sat Aug 12 02:52:16 EDT 2017 | tsvetan
There is no solution in above case, this is caused by the PCB design. There are no thermals on the pads connected to the copper poured area. So the other pad reflow first and lift the component.
Electronics Forum | Wed Aug 16 14:36:06 EDT 2017 | duchoang
Not enough solderpaste. Uneven solderpaste volume on pads. Bad quality of caps ( Metal ends), try new cap manufacturer, sound weird, huh!! but that happened to me. Good luck.
Electronics Forum | Tue Sep 11 09:41:25 EDT 2018 | charliedci
Leo, Your pic is not clear. It appears the LED is either tombstoned or billboarding. A larger pic would help, also component info, how many pads, etc.