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Subject:
From:
"Dehoyos, Ramon" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 28 Aug 2003 09:34:41 -0700
Content-Type:
text/plain
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text/plain (134 lines)
        Victor:
                Paneling is used also at the PWA level to assemble more than
one board ( in the case when boards are small ) or for odd shape boards.
Cracking of components may be caused by vibration when the boards is not
secured properly or if the boards is flexed during the depaneling
        My two cents,
        Ramon.

> -----Original Message-----
> From: Victor Hernandez [SMTP:[log in to unmask]]
> Sent: Thursday, August 28, 2003 10:59 AM
> To:   [log in to unmask]
> Subject:      Re: [TN] Cracking Ceramic SMT Capacitors
>
> Carrie,
>
>     I have experience in PCB mfg. and Component Assembly.   The depaneling
> was always done at the PCB level
> not after Component Placement.   Please provide more details.
>
> Victor,
>
>       -----Original Message-----
>       From: Morse, Carrie [mailto:[log in to unmask]]
>       Sent: Thursday, August 28, 2003 8:54 AM
>       To: [log in to unmask]
>       Subject: Re: [TN] Cracking Ceramic SMT Capacitors
>
>
>       We have seen an increase in cracking.
>       The root cause for us is depanelizing using a rotary style blade
> cutter.
>       Caps and some filters too close to the edge are most subject to
> damage
>       due to the forces imparted on the board when depanelizing.  Often we
>       can eliminate the problem by flipping the board over during
> depanelize, but,
>       that does not always work and since we do not have the tools to
> analyze the
>       forces during the depanelize process, any changes like flipping the
> board
>       over is essentially a bit of a gamble.
>
>       -Carrie
>
>               -----Original Message-----
>               From: Bob Perkins [mailto:[log in to unmask]]
>               Sent: Wednesday, August 27, 2003 7:42 PM
>               To: [log in to unmask]
>               Subject: [TN] Cracking Ceramic SMT Capacitors
>
>
>               Cracking Ceramic SMT Capacitors
>
>               " Is anyone else seeing an increase in the number of cracked
> and shorting ceramic chip capacitors?  In our experience as a contract
> manufacturer we have, in the past, seen the occasional instance of ceramic
> capacitors cracking and shorting out. The cause of this problem is
> generally obvious, as it is isolated to components situated in areas of
> the PCB that are subject to flexing.
>
>               Recently however we have seen more frequent instances of
> this problem; very often in areas of the board that should not be
> experiencing any appreciable flex. Our process has not changed and neither
> have our sources of these components. Have chip capacitors themselves
> become more fragile?"
>
>               Rod Lafond
>               Manager, Quality Assurance and Technical Training
>               APEX-Micro Manufacturing Corporation
>               [log in to unmask] <mailto:[log in to unmask]>
>
>
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