Kiernan,
        another bug in Protel Gerber generation that you will likely run
into soon according to what you have just stated, involves Octagon pads. I
do not know the details as I never use them myself but reportedly Protel
does not generate the correct rotation of octagonal pads in Gerber. Abd-ul
Rahman, Ian Wilson or others are well aware of this issue and can more
suitably define the problem.
        I don't follow your logic on the soldermask issue. If your pad is
drawn with Gerber your soldermask will also be drawn with Gerber, it doesn't
magically draw the pad but then flash the soldermask. The differences you
see in the pad should similarly be reflected in the soldermask Gerber and
there should be no issue. Secondly your soldermask should be expanded by a
few mils by the fabricator (if you don't already expand it yourself) to
allow for slight misregistration during fabrication this will give a little
bit more leeway around your pads.

Sincerely,
Brad Velander.

Lead PCB Designer
Norsat International Inc.
Microwave Products
Tel   (604) 292-9089 (direct line)
Fax  (604) 292-9010
email: [EMAIL PROTECTED]
http://www.norsat.com

See us at Booth S8155 at NAB 2002 in Las Vegas April 8 - 11.


-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]
Sent: Thursday, March 14, 2002 1:26 AM
To: Protel EDA Forum
Subject: Re: [PEDA] Mismatching gerber

Thanks guys. We're using FPC connectors with an 0.3mm pitch. I've got the
pads 
designed so that there's virtually no visible land after soldering, so I
will 
get soldermask encroachment under the pad even though the soldermask lines
up 
with the copper because the pad that I'm getting out of the gerber is
smaller 
than the one on the screen (ie smaller than the pin). At the very least,
I'll 
get severe solderballing.

I've put a sample of the gerber output for a couple of pads below and I
wonder 
whether anyone knows enough about gerber to see if there's a quick fix that 
will produce the correct result. One of the pads is supposed to be a
rectangle 
and the other actually uses the octagonal option.

Are there any other Non-WYSIWYG features that I should know about before I 
spend too many hours on this?? I thought gerber output was the gold standard

for PCB packages.



Cheers


Kiernan Fitzpatrick


%ADD10C,0.0600*%
%ADD11C,0.0150*%
D10*
X102723Y83933D02*
X102879Y83353D01*
D11*
X101100Y83387D02*
X101268Y84015D01*
X101702Y83899D01*
X101534Y83271D01*
X101100Y83387D01*
X101253Y83476D02*
X101356Y83862D01*
X101549Y83810D01*
X101446Y83424D01*
X101253Y83476D01*



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