Is there just one screw close to the QFP or is there more than one? Are you
screwing the PCB to standoffs or studs?

Toby
On Jan 14, 2013 11:56 AM, "Jack Olson" <[log in to unmask]> wrote:

> I understand what you are saying, but in this situation people are
> recommending moving the QFP144 farther AWAY from the mounting structure.
>
> I can't find any guidance in my IPC documents that would suggest an
> appropriate clearance from QFP leads to mounting hardware
>
> Jack
>
>
> On Mon, Jan 14, 2013 at 10:42 AM, Joyce Koo <[log in to unmask]> wrote:
>
> > It depends.  If your board is flexible somewhat and you do require drop
> > test or random vib, and your support points (screw position) is far and
> in
> > between... you might need to worry, not just assembly (flatness is not a
> > issue as you say), but reliability.
> >
> > Joyce Koo
> > Materials Researcher - Materials Interconnect Lab
> > Research In Motion Limited
> > Office: (519) 888-7465 79945
> > Mobile: (226) 220-4760
> >
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Jack Olson
> > Sent: Monday, January 14, 2013 11:36 AM
> > To: [log in to unmask]
> > Subject: [TN] Mounting Hardware to QFP Component Lead
> >
> > To the assembly professionals out there:
> >
> > Have you ever had reliability issues with mounting screws if they are
> near
> > a Quad Flat-Pack? My 144 pin land pattern is pretty close (100mils) but
> we
> > are mounting the board into a very flat structure (no bowing)
> > I can't imagine the compression of the board material could affect
> > gull-wing style lead connections (maybe BGA?) but I don't know...
> >
> > thanks,
> > Jack
> >
> >
> >
> >
>
>
> ______________________________________________________________________
> This email has been scanned by the Symantec Email Security.cloud service.
> For more information please contact helpdesk at x2960 or [log in to unmask]
> ______________________________________________________________________
>


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________