Mail Archives: geda-user/2017/03/17/03:47:07
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On Tue, 14 Mar 2017, Chad Parker (parker DOT charles AT gmail DOT com) [via geda-user@=
delorie.com] wrote:
> =C2=A0- Holes without plating is common.
>
>
> Common, but not essential. The same footprint could work fine
> with plated holes.
>
>=C2=A0
>Not always. In much of my work I'm not allowed to use pth for any kind of
>mounting hole, which would include holes for screwing into things like hea=
t
>sinks and packages that might be included in a footprint.
>
> Question (to all PCB engineers): how often do you rely on the
> clearance value set in a footprint?
>
>
>My clearances are typically defined at the board level by my netlist and m=
y
>geometry. I can't think of a time I've ever defined a clearance in a
>footprint that wasn't highly specialized.
Which means you import the footprint and (in whatever way) change the=20
clearance to fit your board's needs, right? In other words, it doesn't=20
really matter what clearance value is in the footprint, you don't=20
rely on that value.
At least that's what I always do, and I somewhat expected the same with=20
plating.
Anyway, I've added a "hints" field to the hole line. I've also added some=
=20
explanation about how much the plated/unplated hint and the clearance are=
=20
optional. Also updated pcb-rnd to emit and load the new field.
Rationale:
tEDAx is not about trying to unify the internal model of all EDA software.=
=20
It's only about making it possible to share data with low implementation=20
cost, even if that means losing some details. So I keep clearance and now=
=20
it is possible to describe a hint for plated/non-plated, but I don't=20
expect every implementation to fully understand and respect these values.
I believe users should check and fine tune those details when they start=20
using a new footprint from whatever external source. Especially if they=20
are doing something fancy/expensive.
Regards,
Igor2
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