I am currently debating the pro's & con's of suppressing  non-functional
inner layer pads and have found our PCB fabricators have differing views
on which is best. Here are the 2 views.

1.  Suppressing inner layer pads will give a better drilled hole, and so
    will produce a more consistant & cleaner plated hole.

2.  NOT suppressing inner layer pads will produce a stronger & more 
    reliable PTH less prone to failiure.

We first changed to using inner layer pads after a new design, which
required 2 reflow soldering processes & 1 wave solder process, failed
ICT afer assembly.  The cause was a process problem at our supplier which
resulted in via's cracking in the barrel. Having this problem made us
consider what we could do with the design to reduce the risk of similar
problems happening again.

I would appreciate any views you may have on this topic.


  ________________________________________________________________________
 | [log in to unmask]         David Tandy. EDA Specialist.               |
 | Tel: (+44) 161 486 1511     GenRad ADS, Monmouth House, Monmouth Road, |
 | Fax: (+44) 161 486 1989     Cheadle Hulme, Cheshire, SK8 7AY, England. |
 |________________________________________________________________________|


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