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Subject:
From:
Carmen Aloisi <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
Date:
Mon, 19 May 2014 15:16:42 +0200
Content-Type:
text/plain
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text/plain (218 lines)
Hi Steve
here they are, these are the only kind of components that dop the other
ones are well fixed on the pcba.
Thanks a lot,

Carmen

(See attached file: 1.bmp)(See attached file: 7.bmp)



                                                                           
             "Steve Gregory"                                               
             <[log in to unmask]                                             
             et>                                                       Per 
                                       <[log in to unmask]>,                  
             19/05/2014 15:13          <[log in to unmask]>           
                                                                        CC 
                                                                           
                                                                   Oggetto 
                                       RE: [TN] Rif: Re: [TN] pcb issue    
                                       led to smt components drop from pcb 
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




Hi Carmen!

Just reply to this email and I'll post your pictures....

Steve


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Carmen Aloisi
Sent: Monday, May 19, 2014 12:58 AM
To: [log in to unmask]
Subject: [TN] Rif: Re: [TN] pcb issue led to smt components drop from
pcb

Dear all
thanks a lot for your promt reply and suggestions, the pcbs have leaded
hasl surface finishing I agree with you about potential intermetallic
issues... fail pcbas are travelling right now from customer to our plant
here in Italy and then I'll make some cross section.

I'd like to share pictures, how shall I contact mr Steve Gregory in
order to post them?

Have a nice day
Carmen

Carmen Aloisi
Quality Manager

Eutron S.p.A.
Via Crespi 29 24020 Pradalunga (BG) Italy ph. +39 035697011 fax +39
035697090 m. +39 3355666074 www.eutron.com p.i. 01805190160





             Wayne Thayer

             <wthayer@KEYWCORP

             .COM>
Per
             Inviato da:               <[log in to unmask]>

             TechNet
CC
             <[log in to unmask]>


Oggetto
                                       Re: [TN] pcb issue led to smt

             16/05/2014 19:32          components drop from pcb





                Per favore,

               rispondere a

              TechNet E-Mail

                   Forum

             <[log in to unmask]>

               ; Per favore,

               rispondere a

               Wayne Thayer

             <wthayer@KEYWCORP

                   .COM>









Hi Carmen-

You must get the surface analyzed.  I believe that it "looks like" bare
exposed copper, but the odds are highly against that.  As Vladimir has
suggested, you can hire an expert to do the whole analysis.  Or you can
try to make this an educational journey for yourself.  If you get the
surface analyzed, you'll need an analytical technique capable of
identifying the various species and thicknesses of intermetallics which
are on the metal surfaces.

Also, you need to understand the usage environment.  I believe that with
the appropriate amount of temperature cycling, you can get the
components to fall off of anything, provided there is a temperature or
temperature coefficient of expansion difference between the component
and substrate.

Looks like I might be the first to set off some tirades by mentioning
"black pad".  This is a very ugly intermetallic which is associated with
ENIG surface finish, and we providers of electronic assemblies spend
many sleepless nights about it because you can have a beautiful joint
which fails in even fairly mild usage environments.  Obviously we don't
have enough information to suggest this as your problem, but it fits the
final result (as do many other things!).

Shock will take off SMT components also, but that's usually a negligible
probability (exceptions include crystals separating from cell phone
motherboards when the cell phones are dropped or thrown).

Can you provide pictures?  We like to see pictures in TechNet.  You
can't broadcast them directly, and we were using some kind of sharing
site, but this guy named Steve Gregory takes pride in making it easy to
send him pictures and he'll post them.  I think the "cc" address in this
email is his current one, but he's changed companies a few times, so I'm
not positive.
He seems to always watch for opportunities to help like this.

Once you post shots, all of the TechNet experts will come out of the
woodwork with additional questions and arguments guaranteed to be
somewhat amusing and possibly very educational.

Wayne Thayer

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Carmen Aloisi
Sent: Friday, May 16, 2014 11:48 AM
To: [log in to unmask]
Subject: [TN] pcb issue led to smt components drop from pcb

Hello
I'm new to this forum and I'd like to address the following issue to the
group:
after 3 years from delivery of a batct of pcbas we got back from
customer some of them  where components are dropping from the pcbas, the
solder remains on the component pin and the pads are with exposed
copper.
Could you help me in understanding what was wrong on pcb supplier
process or on ours?

Thanks a lot in advance
Carmen Aloisi
Quality Manager

Eutron S.p.A.
Via Crespi 29 24020 Pradalunga (BG) Italy ph. +39 035697011 fax +39
035697090 m. +39 3355666074 www.eutron.com p.i. 01805190160











 .(See attached file: 1.bmp)(See attached file: 5.bmp)(See attached
file:
                                  7.bmp)

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