Electronics Forum | Fri Oct 29 07:10:40 EDT 2010 | scottp
I agree with DucHoang. If your board and reflow profile have not changed then I would suspect incoming parts. We've seen tombstones when a chip supplier had plating problems.
Electronics Forum | Mon Nov 21 10:12:11 EST 2011 | callckq
All, I try to find explanation(Article)on how Nitrogen gas can make tombstone defect even worst. However, I can't find one in the net. Anyone that has this information or article, appreciate if you can share with me...Thanks in advance.
Electronics Forum | Fri Sep 11 01:01:08 EDT 2020 | rsatmech
Thanks for your response. Yes Tombstone is happening in same direction only. We can't rotate every board since the issue is random and the defect rate is around 0.1% Already using high soak profile. Stencil modification in progress.
Electronics Forum | Sun Oct 18 03:01:41 EDT 2020 | rsatmech
Hi All, Thanks for your response and support. Attached is the design used. I found out the below design details in another model. Can used this also. 0.28x0.24 mm is the dimensions available in other model (no tombstone issue occurring).
Electronics Forum | Sat Sep 11 13:49:13 EDT 2021 | kojotssss
Most common causes of tombstoning in our factory: small amount of paste printed on the pcb, improper placement ( pick up process, picked up on the component metallization- large cavity in reel).
Electronics Forum | Mon Sep 13 17:39:02 EDT 2021 | duchoang
Agree. The big pad and part nearby made the paste on two ends of cap melted unevenly.Deposit more paste on the tombstone-ed pad will make it easier to melt. Nothing wrong with profile if everything else is OK. BTW, how to measure temperature on two e
Electronics Forum | Wed May 10 00:27:46 EDT 2006 | Chris
Russ, By a longer profile you mean a more even slope across the entire profile. Unfortunately I only have a 5 zone oven that is fairly short. How many heated zones are you using? Did you shrink the 0402 pad design and leave less pad exposed out a
Electronics Forum | Thu Apr 10 08:23:27 EDT 2008 | scottp
If I read you right the issue is mostly with components from one supplier. I'd suggest looking at the components under a microscope. Also, if you have some old pre-tombstoning parts from this same vendor take close-ups of both and compare them side
Electronics Forum | Wed Apr 12 21:33:27 EDT 2000 | Micah Newcomb
Billy and Chris have a good point, pad size and geometry will affect proper aperture size and geometry and could result in tombstoning. Also I have seen chips which require special pastes but I have never found this to be the cause of tombstoning, in
Electronics Forum | Thu Oct 14 04:12:32 EDT 1999 | Paul Gerits
Hi Jim, I'm a Technical consultant/Application specialist at Philips EMT. Tombstoning is a well know problem with Nitrogen ovens. Proberly there has been a change in your Nitrogen flow or in the nitrogen it self. To see if there was a change run a
