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| Date: | Wed, 19 Mar 2003 16:23:04 -0600 |
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With all other suggestions being considered I have one more comment to add about the ovens you may be using. I have seen in the past if the cooling zones at the end of the reflow ovens are using a radiator system an uneven cooling due to rosin build up
can cause lighter components to tombstone.
I ran across this issue during a build one night and argued that this could not possibly be the root cause of a tombstone issue. The components tombstoning were always the same distance from one edge of the pcb and ran from left to right the full length
of the pcb. We had the radiators changed out for clean ones and this resolved this particular issue.
If all else fails it is worth a consideration.
Darryl Tarpley
SMT Process Engineer
eMS Assembly LLC
Office:(281) 668-1525
Rich Lasko
<RichLasko@BADGERELECTR To: [log in to unmask]
ONICS.COM> cc:
Sent by: TechNet Subject: [TN] Panasonic Film Chip Capacitors and SMT Reflow
<[log in to unmask]>
03/19/03 02:51 PM
Please respond to
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to Rich Lasko
Good afternoon everyone,
I am currently reviewing a tombstoning problem that we are having with the capacitors listed below. We are seeing this problem on two separate electronic assemblies but only with this component style. We place 40 caps per array and approx. 3 - 5 of them
tombstone. Both assemblies go through the SMT process and they both are using a Panasonic ECH-U1H152JB5 and ECH-U1C153JB5 film capacitors. The placement of the capacitors pre-reflow is centered correctly between the pads. But of course post reflow -
tombstone!
Any thoughts, ideas, or experiences with this part would be helpful.
Thanks in advance for your help.
Rich Lasko
Badger Electronics
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