Mail Archives: geda-user/2018/01/29/09:06:34
Bert:
> karl AT aspodata DOT se wrote:
> > Do theese thickness diameters look reasonable ?
...
> > hole c b a aa
> > 0.3 0.8 1.0 1.2 2.5
> > 0.4 0.9 1.1 1.3 2.7
> > 0.5 1.0 1.3 1.5 2.9
...
> - determine lead dimensions and shape (round, square, flat, etc.),
>
> - determine required hole diameter and define in footprint file,
Ok, I use:
my $drill = 0.2 + int(1.01 * $lead_dia * 10 + 0.9) / 10; # round up
wich works for single leads.
> - based on minimal, nominal, maximum accuracy (soldering technology)
> determine drill sizes of board house (round up and use the "even" values
> as in .022, ,024, .026, etc).
>
> - use drill sizes that exist and are actually sold by drill manufacturers !
Ok, 0.1 or 0.05 steps are fine here. Don't know what drill sizes are
available in the US.
> - after layout is finished look at the drill report and optimize for
> minimal drill bit changes.
>
> - so .020, .022, .024, .026, .028 all end up being .028 when the files
> are sent to the board house for production.
Nice idea, thanks.
> - routing goes into a separate (gerber) file ... and do communicate with
> the vendor before actual production starts up.
>
> - YMMV to the gallon ;-)
Aww, you get farther since we measure by the litre.
Regards,
/Karl Hammar
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