Re: gEDA-user: A doubt about umplatted holes.

[Xtian Xultz <xultz@xxxxxxxxxxxx>]

Em Seg 18 Jul 2005 13:43, Darrell Harmon escreveu:
> Xtian Xultz wrote:
> >Hello folks! A good week to everybody!
> >
> >Friday I was talking talking with my pcb fab about unplatted holes.
> >The way PCB does about platted and unplatted holes makes me think that the
> > way fabs do is to drill the platted holes, plate the board and the holes,
> > print the sides, etch, and then drill the unplated holes, am I right?
> >My vendor dont do so.
> >They have only two CNCs to drill boards, and drilling is the most time
> >consuming in the fab process. And a CNC is too expensive. So, making two
> >drill process (for plated and unplated holes) is a great problem.
> >But, he does unplated in this way: if you put a via, with a circle in both
> >sides (like a normal via), the plating stays in the board even next the
> > etch process, but, if the via does not have the circles, i.e. they are
> > only a drill, the plating are etched! I dont know why, but it works! So,
> > what I do here is just a copy and paste from the drill coordinates from
> > the unplated drill file to the plated drill file.
> >
> >My question is, are there more fabs that works so? Would it be a good way
> > to have an option to where the unplated drill go (what file)? Or am I the
> > only one that do this in this kind of way?
> >
> >With best regards to everybody
> >
> >Xultz
> >Curitiba - Brazil
>
> Some of the low cost services I have used do it that way too.  Any hole
> with copper all the way around it gets plated while a hole without an
> annular ring does not get copper.  Most of them don't guarantee that
> there will be no copper in unplated holes.  I have never tried this
> because I only use plated holes.

Thank you for your reply.
I am just affraid of using plated holes for mounting purposes because when a 
board is mounted and solded using wave-of-solder, the mounting holes can 
become closed. There are cases when we need to have plated holes with copper 
anular, but that cannot become closed by solder, this is used when the board 
does not use connectors, but the wires are solded directly to the board. Such 
pin must have the circle cutted, I do this editing the postscript files from 
pcb output in Skencil, but some commercial pcb softwares have this option.