kicad-developers team mailing list archive

[Cirilo Bernardo <cirilo.bernardo@xxxxxxxxx>]

One method which comes to mind is to add yet another hole definition in
software, and that may be the best way to address the problem; this way we
can also ensure the correct thickness of the annulus and check the chosen
number/size of vias.

- Cirilo


On Mon, Jun 8, 2015 at 5:59 PM, Lorenzo Marcantonio <
l.marcantonio@xxxxxxxxxxxx> wrote:

> Having troubles getting an useable workflow with a common usage: the
> mounting
> hole with satellite vias (see attachment).
>
> Rationale: when you have a big hole for a screw and need to have plane
> connectivity, a PTH supported pad is often not a good choice. Mostly
> because on
> the wave solder machine they tend to get clogged (requiring an expensive
> peel
> mask). There are other reason, like ground plane impedance, but
> manufacturing
> convenience is the biggest one :P
>
> So I did the following thing:
>
> (module "HOLE-M4-NPTH" (layer "F.Cu") (tedit 557548BB)
>         (descr "Mechanical Hole, M4")
>         (attr virtual)
>         (fp_text reference "HOLE-M4-NPTH" (at 0 0) (layer "F.Fab")
>                  (effects (font (size 1.2 1.2) (thickness 0.12))))
>         (fp_text value "HOLE-M4-NPTH" (at 0 0) (layer "F.Fab") hide
>                  (effects (font (size 1.2 1.2) (thickness 0.12))))
>         (fp_circle (center 0 0) (end 5.85 0) (layer "F.CrtYd") (width
> 0.01))
>         (fp_circle (center 0 0) (end 5.85 0) (layer "B.CrtYd") (width
> 0.01))
>         (fp_circle (center 0 0) (end 5.5 0) (layer "F.SilkS") (width 0.12))
>         (fp_circle (center 0 0) (end 2.2 0) (layer "F.Fab") (width 0.12))
>         (fp_circle (center 0 0) (end 2.2 0) (layer "B.Fab") (width 0.12))
>         (fp_circle (center 0 0) (end 2.2 0) (layer "Dwgs.User") (width
> 0.12))
>         (pad "" np_thru_hole circle (at 0 0) (size 4.4 4.4) (drill 4.4)
> (layers "*.Cu"))
>         (pad "HOLE" smd circle (at 0 0) (size 8.35 8.35) (layers "*.Cu"))
>         (pad "HOLE" thru_hole circle (at 3.2 0) (size 0.8 0.8) (drill 0.4)
> (layers "*.Cu")
>              (zone_connect 2))
>         (pad "HOLE" thru_hole circle (at -3.2 0) (size 0.8 0.8) (drill
> 0.4) (layers "*.Cu")
>              (zone_connect 2))
>         (pad "HOLE" thru_hole circle (at 1.6 -2.8) (size 0.8 0.8) (drill
> 0.4) (layers "*.Cu")
>              (zone_connect 2))
>         (pad "HOLE" thru_hole circle (at -1.6 -2.8) (size 0.8 0.8) (drill
> 0.4) (layers "*.Cu")
>              (zone_connect 2))
>         (pad "HOLE" thru_hole circle (at -1.6 2.8) (size 0.8 0.8) (drill
> 0.4) (layers "*.Cu")
>              (zone_connect 2))
>         (pad "HOLE" thru_hole circle (at 1.6 2.8) (size 0.8 0.8) (drill
> 0.4) (layers "*.Cu")
>              (zone_connect 2)))
>
> I have a big SMD round pad on all layers for the support copper, an NPTH
> hole
> for the drill tape, and common pads for the satellite vias. The
> zone_connect forces solid fill, not that it would have really mattered
> (since there is the big pad covering all). Less cruft in the gerbers...
>
> Problem #1: pad snap always pick the big SMD pad and the track get
> rejected because it falls into the NPTH hole; workaround: disable pad
> snap and locate it by hands. Not a big issue since usually these are
> tied to fills and they attach correctly.
>
> Problem #2: the big pad and the NPTH hole are conflicting in the DRC
> (quite correctly, in theory). However that's a PITA because the message
> can 'obscure' more severe errors.
>
> Any idea on how to solve this?
>
> --
> Lorenzo Marcantonio
> Logos Srl
>
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