Re: gEDA-user: pcbexpress.com and ``pcb'' ``negative'' solder mask layers

[Karel Kulhavy <clock@xxxxxxxxxxxxx>]

On Thu, May 19, 2005 at 09:53:35PM -0400, Joel N. Weber II wrote:
> A google search of the archives of this list seems to suggest that
> someone who's posted here in the past has successfully made 4 layer
> boards using ``pcb'' and pcbexpress.com; I assume this probably
> included soldermask layers.
> 
> I tried ordering a two layer (that is, two layers of copper, two
> layers of soldermask, one layer of silkscreen, plus the drill file)
> board from pcbexpress today, and got back:
> 
> | Your Order [order number] IS HOLDING...  Both the top and bottom
> | soldermask layers are negatives.  We require positive layers for
> | all.
> | 
> | Please reply to this email and attach new or revised files; your
> | order will be processed ASAP.
> 
> Do people have recommendations about how to deal with this?

I send Gerbers with explanation about negativity/positivity to the
manufacturer:

http://ronja.twibright.com/schematics/README

IMHO serious manufacturers shouldn't have problems with this, inverting
it on their own.

I hit one manufacturer I consider non-serious who wasn't able to
correctly read Gerber RS-274X although he was advertising it as
supported format.

But if you edit the file manually and change IPPOS to IPNEG and
vice versa (maybe something elese will be necessary, see Gerber doc
http://nexp.cs.pdx.edu/twiki-gerber/pub/Gerber/GerberFiles/rs274xrevd_e.pdf
), you should be able to end up with inverted polarity.

> Also, it seems slightly inconvenient that pcb is designed to generate
> separate drill files for plated and unplated.

How would you distinguish the two hole types in one file?

CL<