That's a typo, right? If the holes without pads fail first, shouldn't you
have said ".... - so I do NOT allow removal of redundant inner layer pads"?
Cheers........
Andy K.
+61 2 9499 4853
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Paul O
Connor
Sent: Thursday, 5 August 2010 16:47
To: [log in to unmask]
Subject: Re: [DC] Fwd: non-functional pad removal
I carried out thermal shock testing on 12 Layer 2oz cu daisy chain PTHs
boards, Aspect ratios of 4:1 & 6:1 with 4 different hole wall thicknesses
(from 22um up to 70um) approx 1300 Test hours
the results shows the holes with pads removed fail first independent of hole
wall thickness or aspect ratio - so I do allow removal of redundant inner
layer pads.
On Wed, 4 Aug 2010 09:26:03 -0500, Jack Olson <[log in to unmask]> wrote:
> oops, I said it wrong. I went back to my notes, Brian Ellis said keep them
>in:
>
>-=-=-=-
> Subject: Re: non-functional pad removal
>From: Brian Ellis <[log in to unmask]>
>Date: Tue, 13 Jul 2010 08:45:21 +0300
>If the inner layer copper thickness is >35 µm (and sometimes 35 µm),
>e.g., power planes, then you should keep the copper there for fear of
>resin starvation.
>Brian
>-=-=-=-
>
>
>Also, I think I might have said some thing else wrong...
>Werner said on July12
>"To prevent the latter, remove NFPs from large diameter holes and leave
them
>in place for small diameters."
>and I said that backwards in my sample note
>
>and just now on aug04 Werner said:
> "Don't remove NFPs from layers 1,2,3,n-2,n-1,n—FOR LARGER DIAMETER HOLES"
>Now I'm not sure what to remove and what to leave
>
>(and I'm just an instigator, no knowledge of this subject)
>
>Jack
>
>On Wed, Aug 4, 2010 at 8:56 AM, Dave Schaefer <[log in to unmask]>
wrote:
>
>> Jack,
>>
>> Thanks for summarizing here, I do also monitor Technet but find it's
>> difficult to locate topics of interest without plowing through a lot of
>> unrelated and often NTC content there.
>>
>> There's a part of your summary that I can't seem to digest :
>>
>> "In additon, there was a direct conflict between two comments, one
>> recommended removing NFPs for thick power planes (BEllis), the other said
a
>> DOE testing 24 layers of 2oz was more reliable with NFPs removed
>> (GGagnon)."
>>
>> Both comments seem to indicate thick power planes should have NFPs
removed
>> -
>> can you clarify?
>>
>> Thanks,
>> Dave
>>
>>
>
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