Re: gEDA-user: single-sided boards

[David SMITH <dave.smith@xxxxxx>]

On Sat, Feb 28, 2009 at 02:21:23PM -0500, Stuart Brorson wrote:
> > How often does the need for single-sided boards arise?
> 
> The question about single-sided boards is interesting, but the
> answer depends upon how you intend to fabricate your boards.
> 
> If you're sending the boards to a PCB manufacturer, then the raw
> material they use is fiberglass clad with copper on both sides.  In
> this case, it's senseless to ask for a single-sided board to save
> costs -- they start with a double-sided board in any case.

However, some of them do provide a cheaper, single-sided service - even
the low-volume "panellising" companies - for example, www.pcb-pool.com.

If they are starting from double-sided stock, then they can save on
the production of an artwork - just expose the "component" side fully
(or not at all, depending on whether their photoresist requires a
positive or a negative exposure).  They can also save on through-hole
plating.

When I've used their single-sided service before, I just sent them my
whole data file (yes, I know, I'm a sinner - I use a commercial PCB
design package), and asked them to do just the bottom copper layer.

> I agree that it tends to trip up newbies.  However, there's one Gerber
> file per (metal) layer, so you can always discard the back side file
> without any problems.

That's what I was going to say :-)

> Finally, one of the projects slated for work under the Linux Fund's
> PCB project is to update PCB's handling of layers.  Things like the
> ability to easily deal with single sided boards from inside of PCB
> are part of the work to be funded by the Linux Fund. I'll just remind
> everybody that they can make this work happen sooner by making a
> donation!

If I may make a suggestion - "solve" the layer handling problem which
prevents PCB's data files from being taken directly by companies like
www.pcb-pool.com.  (I think it's something to do with the fact that
the file doesn't contain any info to define the meaning of each layer
(e.g. top copper, bottom copper, etc.)

Gerber is such a vile format; it's time it was consigned to the
scrapheap :-)

-- 
David Smith            Work Email: Dave.Smith@xxxxxx
STMicroelectronics     Home Email: David.Smith@xxxxxxxxxxxxxxxxxxxx
Bristol, England          GPG Key: 0xF13192F2


_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user