Electronics Forum | Thu Feb 24 11:02:29 EST 2000 | mark scheunemann
I am looking to discuss 0402 issues, specifically tombstoning/unsoldered. Any recommendations on pad size/spacing, stencil design etc would be helpful. Placement and reflow profile look good.
Electronics Forum | Wed Jul 01 08:15:13 EDT 2009 | dwelch123
You can use regular paste and a .005 stencil will help reduce tombstones. It's just that easy. I run 0402's all the time without any problem, just make sure your profile is a good one!
Electronics Forum | Thu Apr 11 14:31:15 EDT 2002 | aaelect
We're having some problems with 0402's tombstoning. On a board with about 300 parts we're getting about 12 to 20 tombstones per board. The caps seem to do it more often than the res. The pads appear to be in accordance with IPC SM 782 amendment 1, S
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 | Thu Jul 02 10:52:45 EDT 2009 | dyoungquist
For 0402s we use type 3 paste. We have .006 and .005 stencils. The .006 works okay but .005 seems to give us slightly better results. We use a 1:1 ratio for the aperture to match the pad, round pad not needed. With accurate placement and a correc
Electronics Forum | Thu Jun 02 15:56:42 EDT 2005 | jimmygam
run the board thru both backward and sideways and see what happens
Electronics Forum | Fri Jun 24 15:37:24 EDT 2005 | KT
Also check for any Vian-in-pad designs that could cause the problem.
Electronics Forum | Tue Dec 26 11:26:00 EST 2000 | acahill
If you have a known problem with the parts, then Reject them back to the Vendor. It appears that you have a solderability issue. As for Tombstoning on 0402 chips, this could trace back to the stencil design and/or machine placement. Define Tombstoni
Electronics Forum | Thu Jun 02 14:50:41 EDT 2005 | techknow..
Placement looks good...paste to pad coverage good..correct profile used and verified by tracker. The problem being that this one cap is tombstoning at the same place every time. The placement is central. The part is near the edge at the break off.
Electronics Forum | Tue Jun 14 18:37:18 EDT 2005 | GS
On top to above suggestions,Round pad designe (where possible to get) helps to solve tombstoning pbm. Regards GS
winsouce.jpg)