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Date:	Tue, 3 Feb 2015 08:22:16 +0100
From:	Gabriel Paubert <paubert AT iram DOT es>
To:	geda-user AT delorie DOT com
Subject:	Re: [geda-user] Footprint Generator
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On Mon, Feb 02, 2015 at 06:42:12PM -0800, Edward Hennessy wrote:
> 
> > On Feb 1, 2015, at 8:28 PM, Kai-Martin Knaak <kmk AT familieknaak DOT de> wrote:
> > 
> > Edward Hennessy wrote:
> > 
> >> I've created a GUI footprint generator for PCB.
> > 
> > Yet another suggestion:
> > 
> > Add the ability to make thru hole pins oblate on the solder side. This 
> > facilitates manual soldering and still allows for a signal or two to 
> > go between two pins.
> > 
> > In pcb pins can only have a round shape. But there is a trick. You can 
> > add a pad with the same 
> > 
> > See my DIP footprints for an example:
> > http://www.gedasymbols.org/user/kai_martin_knaak/footprints/generic/DIP/DIP8.fp
> > 
> > (The oblate pins do not show in the preview of gedasymbols.org. 
> > Probably, because they are on the bottom layer, only.)
> 
> This looks relatively easy to implement. I'll add this to the issues as an enhancement.
> 
> I don't have experience on the CAM side of fabrication. But, this technical article recommends against "painting pads."
> 
> http://www.ucamco.com/files/downloads/file/12/the_scourge_of_cad-to-cam_communication.pdf

Yes, and it would be good to fix PCB Gerber generator to flash all pads
(pins and vias are typically flashed).

> 
> Does anyone else have experience with these issues on the CAM side?
> 
> I've seen some pads that are circular at one end and square on the other end. Is there a limit to how far this technique can go?
> 

Not really (yes there are some limits, but hard to hit in practice).
It is possible to define fairly complex apertures in Gerber, or to
compose them directly by flashing a few simpler ones. Now this may
depend on your PCB manufacturer's equipment: for a long time the Gerber
specification had a limit of ~990 apertures (from D10 to D999), the
upper limit was raised to 2**31-1 a few years ago (in practice this is 
equivalent to infinity, can you imagine a board with over 2 billion
pads, all different?), but old, and not so old equipment may have 
trouble handling files with thousands of apertures.

    Gabriel

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