Stupid questions, sorry...
1.) "...should be more vocal about large holes (as one example, bigger than
.125") in GIL systems and the risks involved,..."
Risks involved -- __________________
2.) "... and the associated risks when there isn't the support of un-used
pads left in the artwork...I found this out the hard way."
Found out --- ______________________
Regards
-----Original Message-----
From: Stephen R. Gregory [mailto:[log in to unmask]]
Sent: Monday, October 04, 1999 6:18 PM
To: [log in to unmask]
Subject: Re: [TN] PCB Manufacturers
In a message dated 10/4/99 7:44:43 PM Central Daylight Time,
[log in to unmask] writes:
> TechNet,
>
> I would like to throw in my two cents...before this subject goes from
> amusing to outright ugly...
>
> I disagree with some of the comments made by a few people on this
subject,
> as a matter of fact I have experienced quite the opposite first hand.
"Just
> build it the way it is designed" or "Just follow the drawing and leave
the
> thinking to us" is a quite common answer that I guess all PCB
manufacturers
> receive every day.
>
> In my company (as I guess in many others around the US and the whole
planet)
> we have the bad habit of checking the artwork for manufacturability
before
> we even start building the board - I am sure that most of my colleagues
will
> agree that 90% of the times the designers and engineers on the other side
of
> the phone line completely ignore all the manufacturability
> improvements/changes proposed by the PCB Fabricator.
>
> Sorry, but after that I can't find anything wrong in building a product
that
> follows the specifications and the requirement that were given to me, we
may
> ask but if we are not allowed to fix anything we build it the way it is.
Kiko,
You are "abso-tively" correct! In my relatively "fresh" experience in this
arena, I've found that the military, and hi-rel boards are the absolutely
biggest nightmare when it comes to DFM...
There are spec's that are out there that make absolutely no sense when it
comes to what we all know now, but because of the 'friggen paper trail that
has to accompany ANY change to the drawing, no one wants to try and tackle
it... and this comes from the customers themselves. So what do we do? We are
all taxpayers and we pay for this stuff?
Who do we go to and say that the design for a national security product is
outdated? Why do we deal with obsolete technology ideas that was first
learned about 20-years ago and try to change it?
I'm a old fart too, but I can learn new tricks...the system that we have
when
it comes to electronics for the government and military have such a
cumbersome way of changing the design to take advantage of new developments,
that we all continue to try and build assemblies that are un-manufactuable
in
most cases...
This thread should be on the designers forum...
But again, the fab shops in my opinion, should be more vocal about large
holes (as one example, bigger than .125") in GIL systems and the risks
involved, and the associated risks when there isn't the support of un-used
pads left in the artwork...I found this out the hard way. I also learned
that
a decent test coupon should include ALL the circuitry and holes...NOT just
the IPC test coupon! Think about it, be pro-active!
-Steve Gregory-
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