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Subject:
From:
"Thayer, Wayne" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Thayer, Wayne
Date:
Fri, 19 Sep 2008 00:18:29 -0400
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I see you have a comment in there about "acid traps".  I researched this lore several years ago and if it ever had any applicability, it seems to be gone now.  Etching acids are designed to eat just a tiny bit of copper and then fall back into the sump.  They act like hungry little piranhas with very tiny bellies, so wherever they puddle up and stagnate, the etching action is much diminished.  Whenever I try to etch an acute angle, it automatically gets a fillet, even if there is none on the imaged/developed panel.

So I put my "acid trap" right next to my "water hammer".

Wayne Thayer

________________________________
From: TechNet on behalf of Jack Olson
Sent: Wed 9/17/2008 2:44 PM
To: [log in to unmask]
Subject: Re: [TN] FAB:CAD2CAM


A few months ago I blasted several discussion forums with questions
about the process of moving data from CAD to CAM

I got a lot of interesting and informative responses, and I just wanted
to thank everyone for taking the time to help out.

It hasn't been published yet, but I compiled everything I learned about
this subject into a PDF that you can read if you are interested.

http://www.frontdoor.biz/PCBportal/CAD2CAM.pdf

If you have any other comments or suggestions, please don't hesitate
to write back (its not too late to make changes)

Thanks again,

Jack
[log in to unmask]



.
On Wed, May 14, 2008 at 3:28 PM, Jack Olson <[log in to unmask]> wrote:

> I've recently had the opportunity to spend some time with "the CAM guy" at
> our primary circuit board supplier, and now a magazine has expressed an
> interest in publishing an article about what happens to data as it moves
> from CAD through CAM. If any of you are involved in this process, here is
> a golden opportunity to voice your concerns (or your "wish list"). I already
> have my notes for what happens to OUR data, but I would like to be more
> generic for the magazine.
>
> If you aren't doing CAM work but know someone who might like a shot at
> this, PLEASE forward this to them.
>
> The most surprising thing I learned this week was the extremely low
> percentage of jobs being submitted in an intelligant format. For example,
> we've been told for years to move to something like ODB++ or GENCAM, but I'm
> hearing that maybe only a few percent of the jobs are anything other than
> regular old Gerber. Is that true? Would it help you significantly to get
> some alternative to Gerber?
>
> I'm also interested to hear anyone's thoughts on the note that can be found
> on many drawings that says:
> "DATA SHALL NOT BE MODIFIED WITHOUT WRITTEN APPROVAL".
> Where do we draw the line on that?
> Plot film with data "AS IS"?
> How does it apply to
> etch compensation?
> removal of non-functional pads?
> teardropping?
> silkscreen clipping?
> What is "standard" editing, and what really should be pre-approved?
>
> We've been told to always place the origin on a tooling hole. Does it
> really matter?
> Would you rather have the soldermask 1:1 with the pad size and enlarge it
> yourself?
> Would it help you much to have positive planes drawn with unique aperture
> sizes?
> Does the format matter? inches? metric? consistent with drill?
> Would it help to have better README files that explain more of our
> intentions?
> (like a known netlist discrepancy, for example)
>
> What do you wish more people would do to make your life easier?
>
> Maybe its inconvenient to answer so many questions, but if we have a chance
> to teach designers what we want, shouldn't we try?
> (I'm gonna write it with you or without you, so don't complain if what gets
> published is off-grid)
> Also, If I didn't ask the question you want to answer, don't hesitate to
> add to the list!
>
> If YOU were King of the World for a day, what would you change?
>
> Thanks in advance,
> I'll try my best to write a fair and thorough article
>
> Jack
> [log in to unmask]
>

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