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July 2001

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Subject:
From:
Edward Szpruch <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Mon, 30 Jul 2001 18:08:39 +0200
Content-Type:
text/plain
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Daan,
Only after  your second mail I took a look on the right spot...
You wrote,that adhesion on those spots is bad and going worst after
soldering, so this is clear delamination.The point is,if the problem is only
on those spots,or after reflow is expanding.
You should ask a lot of questions the manufacturer of those boards,since a
lot depends how the board is build.Those spots might be results of
drops,that attacked oxide treatment ( it seems,that copperplane is treated
in this way. If coverlay is based on acrylic adhesive,this might be  epoxy
dust,that was not cured during coverlay lamination stage,which is done in
lower temp. compared to epoxy cycle.This can be also the original
antioxidation layer applied on the raw flexible material . Another point to
discuss with the manufacturer of the rigid-flex - what are the chances to
have it in rigid area ( it might be inside,but you can not see it due to
stack of rigid layers with big land areas inside) etc...
Good luck 
Edward
Edward Szpruch
Eltek , Manager of Process Engineering
P.O.Box 159 ; 49101 Petah Tikva Israel
Tel  ++972 3 9395050 , Fax  ++972 3 9309581
e-mail   [log in to unmask]

> -----Original Message-----
> From: d. terstegge [SMTP:[log in to unmask]]
> Sent: α ιεμι 30 2001 15:47
> To:   [log in to unmask]
> Subject:      Re: [TN] Flex delamination?
> 
> Thanks Steve,
> 
> Here's some extra info about the picture:
> 
> Before my destructive experiments with removing the coverlayer (always a
> pleasure! ) this discoloration showed through as dark spots, some about 1
> cm diameter. The material still looked flat, unlike most delaminations
> that I've seen, and that's why I'm not sure if this really is a
> delamination. After cutting the flex with scissors I found out that at
> these spots there is very bad adhesion between copperplane and coverlayer.
> 
> Although the copper has a greenish color, it looks smooth and shiny. This
> was already somewhat visible before assembly, but it became worse during
> reflow soldering.
> 
> Daan
> 
> >>> <[log in to unmask]> 07/30 3:32 pm >>>
> Hi Everyone!
> 
> Still hot as Hades, here...looks like we're looking at +100-degree days
> all 
> this week!
> They did an interesting thing on one of the local news station here to 
> illustrate how hot it gets inside a car, and why it's really crazy to
> leave 
> kids or pets inside cars when it gets this hot...they actually baked
> cookies 
> inside a car!!! Enough of that...
> 
> Daan's asked me to post a picture for him up on our web site. Go to:
> 
> http://stevezeva.homestead.com/index.html 
> 
> I've got a picture of a flex-rigid board with a greenish spot on the 
> copperplane, under the coverlayer. I would like to know what this is, and
> if 
> it we should reject it or not.
> 
> Daan Terstegge
> SMT Centre
> Thales Communications
> Unclassified mail
> Personal Website: http://www.smtinfo.net 
> 
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