Re: gEDA-user: PCB pin hole size

[John Luciani <jcljr58@xxxxxxxxx>]

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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