In talking to some PCB assemblers recently (IBM Wangaratta), they
recommended 0.02" pad-pad for untented vias so that there will not be
(any?) shorts.

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On Fri, 24 Apr 1998, Shaub, John (PA62) wrote:
> Cor,  I suggest you use Dave Wolfs (from Hadco, next post) equation to get
> your spacing. In other words find the
> minimum pad diameter and drill size. Then add the pad-to-pad spacing you are
> using in your design.
>
> Example:  Finished hole size is .012 and your pad-to-pad spacing rule for the
> design is .008, the closest any two
> vias can be to each other with these rules is .034.
>
> Of course the tighter the rules, the closer the vias become.
>
> Hope this helps.
> John E. Shaub


>> Would anybody happen to know what a safe spacing can be
>> between vias, not covered with solderresist, in order to avoid
>> PBSN-bridging during wave soldering
>>
>> Thanx in advance and best greetings to you all,
>>
>>
>> Cor Coolen.

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