Well...  I have found that as a CAM operator in my earlier days, that removing the non-
functional pads on internal layers really had no effect of the reliability of the product being 
built.  I think that this has come to be more of a preference method of building a PCB.  As for 
possible drawbacks to removing the non-fuctional pads, the internal walls of any pth has 
less of an adhesion to the wall of the hole
(ie, the pads act sort of like anchors strengthening the hole wall and preventing peal away 
from the barrel of the hole.  But, if your copper-plating process is up to modern day plating 
specs., then I would not worry about removing the non-fuctional pads.  One other thing to 
keep in mind is that some customers call out in their mfg specs. that non-functional pads 
NOT be removed.

Continued Success....


Lyle Dove
GCA Technology Support Division
[log in to unmask]
http://www.gcatech.com



In your message you wrote:

>From: <[log in to unmask]>
>To: <[log in to unmask]>
>Cc: 
>Date: Tue, 15 Jul 1997 15:32:42 -0500
>Subject: FAB: Padless vs. Padded

>With regards to my last email, the terms supported meant, with a land/pad and 
>unsupported meant without lands/pads.  Here it is again with padless replacing 
>unsupported.
>
>
>     Address,
>     
>     Are there any Technical Publications on comparing the reliability of 
>     padless and padded vias/pths?  What other avenues should I be concerned 
>     with should I have padless vias and pths (internal and external) where 
>     conductors do not intersect?
>     
>     My reading up until now says padded vias and pths are more reliable 
>     than there counterparts.  Does this still hold true?  All other vias 
>     and pths will have A/Rs and teardrop pads with no tangent and/or 
>     breakout at the egress.  
>     
>     Pass the info.  Please advise.  Later
>     
>     John Gulley









Lyle Dove
GCA Technology Support Division
[log in to unmask]
http://www.gcatech.com


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