kicad-developers team mailing list archive

[Alex G <mr.nuke.me@xxxxxxxxx>]

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On 09/09/2010 12:34 AM, Lorenzo Marcantonio wrote:
> On Wed, 8 Sep 2010, Alex G wrote:
> 
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>> Oyvind,
>>
>> I believe it would make sense, for the D-SUB connectors, to only place
>> the pad on the back side, so as to free up space for tracks on the front
>> side. I'm not sure if this is necessarily wise (problems with
>> through-hole plating?), but I'm throwing it as an idea. What do you
>> think?
> 
> Usually PTH components should have pads on both faces for 3 reasons:
> 1) A pad on a single layer is prone to delamination (especially if you
> need to rework it; the plating barrel and the opposite pad have great
> effect on mechanical strength;
> 2) If there is a plating barrel and hole clearance is correct the whole
> hole would be filled with solder (better electrical and mechanical
> performance);
> 3) You would forfait access to *all* the other layers (for example
> supply planes); also is almost impossible to route all the pins from an
> HD connector on one layer keeping solder pads big enough for good
> joints.
> 
> Since at the moment kicad hasn't a padstack facility (i.e. for reducing
> pads on the inner/components layers) it should be user that, only when
> needed, would remove the pad.
> 
Wouldn't it then be feasible to create the normal 7.4mm pad on the back,
and leave a smaller pad (say 4mm) on the front (and maybe inner layers),
or is this getting too complicated to be of any practical use?

Alex
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