That was very Admirable of you catching my intended humor.
Dewey
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
Sent: Tuesday, January 15, 2013 9:49 AM
To: [log in to unmask]
Subject: Re: [TN] Mounting Hardware to QFP Component Lead
At least you've corrected Dewey's Decimal!
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Whittaker, Dewey (EHCOE)
Sent: Tuesday, January 15, 2013 11:41 AM
To: [log in to unmask]
Subject: [TN] FW: [TN] Mounting Hardware to QFP Component Lead
My apologies. In switching to HTML format to use symbols, I missed my point (decimal , that is). I meant 0.25". It is much better to be diametrically opposed, than having you’re point missed altogether.
Dewey
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Whittaker, Dewey (EHCOE)
Sent: Tuesday, January 15, 2013 9:25 AM
To: [log in to unmask]
Subject: Re: [TN] Mounting Hardware to QFP Component Lead
There are many divine principles, disciplines, mandates and theoretical dogmas that have not made their way into IPC-2221, why would you expect this question, with all the good previously alluded to variables and potential mitigating scenarios, to be covered with a standard keep-out area?
Since you asked again I'll accept your naiveté on this subject matter and state; 0.025 " keep-out clearance from edge of hole to nearest pad geometry.
Dewey
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jack Olson
Sent: Tuesday, January 15, 2013 8:37 AM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Re: [TN] Mounting Hardware to QFP Component Lead
True, but I can't help but wonder if I'm missing something...
Of all the issues that the IPC committees have discussed over the last few DECADES, why can't I find anything about mounting structures to component clearance?
hmmm... dar's gotta be sumpn 'bout dat!
thanks anyway,
Jack
.
On Mon, 14 Jan 2013 19:16:27 +0000, Wayne Thayer <[log in to unmask]<mailto:[log in to unmask]<mailto:[log in to unmask]:[log in to unmask]>>> wrote:
>If it is a new QFP with the pure copper/very high copper leads then I wouldn't worry about it. Those leads are so compliant they can absorb amazing amounts of stress.
>
>Wayne Thayer
>
>-----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]<mailto:[log in to unmask]<mailto:[log in to unmask]:
>[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
>
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