Re: gEDA-user: PCB pin hole size

[Xtian Xultz <xultz@xxxxxxxxxxxx>]

My vendor uses the drill size as the size of the bit. So, if I will made a 
single sided board (without tin plating nor hot air process) I use one size. 
Like, for an PTH IC I use 28 mils (0,7 mm) if it is a prototype, and 32 or 
(better) 36 mils (0,8 and 0,9 mm respec.) for a production board.
If I made a double side board with tin plating and hot air I use 32 mils for a 
prototype board and 36 or 40 mils for production board.


Em Ter 25 Jan 2005 11:45, John Luciani escreveu:
> You need to check with your board vendor.
> I believe AP circuits treats the value in the drill
> file as a drill diameter. It is up to the purchaser
> to accommodate for the plating.
>
> PCB Express uses the value in the drill file as a
> finished hole size and they account for the plating
> dimensions. This seems like the correct way to do it.
>
> When I create parts I used the finished hole size.
> My PCB file then represents exactly what is required
> to create a physically correct board. If I want to
> send the board to a different vendor I can post
> process
> the drill files to accommodate for the differences
> in the new process.
>
> If you adjust your drill sizes you need to be careful
> that there is sufficient copper remaining after the
> drilling operation to reliably plate (annular ring).
> Since most vendors have a wide variety of drill sizes
> this should not be a problem.
>
> (* jcl *)
>
> --- Wojciech Kazubski <wk@xxxxxxxxxxxxx> wrote:
> > > Somebody said that handmade single-sided boards
> >
> > can use the smaller
> >
> > > holes.  This _may_ be true, but they could also
> >
> > use the larger holes
> >
> > > without trouble.  The library should be fixed or
> >
> > removed, not left as
> >
> > > is with a warning.
> > >
> > > Matt
> >
> > Shold the specified diametr be the drill size or
> > finished hole size?
> > The above values may differ by a few mills or about
> > 0.1mm due to plating
> > thickness.
> > The first is safer, but the second one is less
> > technology dependent.
> >
> > Wojciech Kazubski
>
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