Re: gEDA-user: [pcb] solder mask polarity

[Dan McMahill <dan@mcmahill.net>]

On Sun, 20 Jul 2003 13:12:08 -0400
Dave McGuire <mcguire@neurotica.com> wrote:

> On Saturday, July 19, 2003, at 05:58 PM, Dan McMahill wrote:
> >> Ok, after a number of emails back and forth with the folks at
> >Advanced> Circuits, I learned that the "industry standard" for solder
> >masks is> to print them with positive polarity (i.e. dark where you
> >want solder> to go) - you're specifying the reliefs, not the mask
> >around them.> Apparently, some shops will accept either and just fix
> >them as needed.>
> >
> > For professional boards I've always sent the soldermask relief as a
> > positive layer, ie, dark where solder goes as you said.  The boards 
> > I've
> > done with PCB were fabbed by a low cost place and I didn't get
> > soldermask on those.
> 
>    Hey Dan, would you mind if I asked which board house you use, and 
> could you (if you have a spare moment) give me a quick rundown on what
> 
> you sent to them, and any other information they require?  I'll be 
> doing a board with PCB very soon and I need to find a cheap board
> house to fab them.

for quick turn 2 layer boards without soldermask or silkscreen, I've
been pretty happy with APCircuits.  They're cheap, quick, and so far,
totally painless.  Basically you send them top and bottom copper plus
the NCD file (drill info) and a list of drill sizes (even though its
embedded in the NCD file).  They have a windows app that assembles
things and sends it off.

for more involved boards I've used Advanced Circuits (4pcb.com), Bay
Systems (I think that was the name), and Sovereign for multi layer
boards.  In that case you need to send gerbers for all copper layers,
top and bottom silkscreen (if you want it), and top and bottom
soldermask relief.  I've also typically sent them a drill drawing in
addition to the NCD file.  There really are quite a number of board
houses around with varying process capability.  I've used CFC in Waltham
MA too, but felt that the silk registration was a bit sloppy.

Of all these, APCircuits was the smoothest the first time I used them. 
In fact, I've never had any direct communications with anyone there.
 I send the stuff, 2 days later I have boards.  Sovereign was also
easy, but the company I worked for at the time ordered a very large
number of new board designs a year from them so any initial kinks had
been worked out long before I was there.

-Dan