Nicely said, Bill!
Bill Gebhardt, C.I.D.
Electrical Engineer
IPC Certified Interconnect Designer
Overland Storage, Inc.
San Diego, CA
(858)495-4222
[log in to unmask]
Treasurer - IPC Designer's Council, San Diego Chapter
"Brooks,Bill"
<[log in to unmask]> To: [log in to unmask]
Sent by: cc:
Subject: Re: [DC] Core thickness/emissions
DesignerCouncil
<DesignerCouncil@listse |-------------------|
rv.ipc.org> | [ ] Expand Groups |
|-------------------|
06/09/2003 08:37
AM
Please respond to
"(Designers Council
Forum)"; Please respond
to "Brooks,Bill"
I think Alexis was right to bring up the subject and I think it shows that
most of us understand the problem and critical nature of the design
requirements being spelled out in such a way as to not 'get it wrong' or
inconsistent from one vendor to another. The science that goes into the
design needs to be repeatable and consistent from one vendor to another and
you, the designer, control this with the appropriate notes and details on
the fab drawing.
On the other hand, if it is not a critical feature, please don't tie the
board vendor's hands.... Give them the allowable freedom to change things
that ARE NOT CRITICAL that favor their processes. (The question is... Is it
critical in this case?)
Let's say that the designer on this board went to a seminar and saw a
demonstration that defined the board stack up in great detail much in the
manner that this board is done, and he/she decided to use a similar tight
specific definition on all their boards regardless of the need to do so....
because it looked cool and impressive and made everyone think they knew
what they were doing. The board vendor has no way to know if the designer
specified the layering structure and types of materials and thickness
requirements unnecessarily or not. They have to assume that you know what
you are doing and that they may not deviate from it if they want your
continued good business. Most boards do not need this type of treatment.
Many RF applications DO NEED this kind of detail.
Perhaps this board MAY NOT NEED to be defined in the fashion it is and
COULD be altered without any undue harm to the layout and assembly. We just
don't know that without more information, but it's interesting to see the
other comments and assumptions. I did not see anything in his original
question that stated that the boards were already MADE. Perhaps they are in
the shop preparing to make them. As I would expect the shop to do, they
should call the designer with a question before taking any action.... And
indeed that seems to be the case. To lambaste the guy or shop is to jump to
conclusions... let him explain it more before calling him "dumb". That's
just rude JaMi.
The intent here is to learn from each other and we do not know it all. None
of us 'Know it all'. But we can fill in the gaps for each other and
collectively we are more than the individual could ever hope to be. Let's
use the forum to HELP each other not embarrass or ridicule.
Best regards,
Bill Brooks
-----Original Message-----
From: Tom Garman [mailto:[log in to unmask]]
Sent: Monday, June 09, 2003 8:05 AM
To: [log in to unmask]
Subject: Re: [DC] Core thickness/emissions
Jami;
Alexis is competent enough to ask the right questions. Most of the
people I have dealt with consider the other person to be competent
until proven otherwise. From your posting I can see that you have not
had the same experience. I have worked in situations where I had to
prove my competence. I did not enjoy those jobs very much. Most board
designers do not have advanced degrees in electrical engineering nor
are they clairvoyant. In my viewpoint it is a waste of an engineer's
time to be laying out boards. The engineer should be reviewing the
layout but unless he is at the low end of the salary scale it is not
cost effective for him to do layout.
PS I don't need to brag, I have witnesses.
Tom Garman
PCB Designer
330-575-1636
[log in to unmask]
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]]
On Behalf Of JaMi Smith
Sent: Saturday, June 07, 2003 3:00 AM
To: [log in to unmask]
Subject: Re: [DC] Core thickness/emissions
Eric,
Unfortunately, it is not a joke.
I was just about to say that you obviously do not have any
concept of what emissions testing is all about, either
practically or legally, but then I looked at your email address
and realized that you really do understand what is going on
here, and appear to just be making light of it.
It is not just a question of simply radiating interfering
signals when you are dealing with a cell phone company that
makes an RF Transmitter that people hold up to their heads.
It also appears that you may have never spent long hours in
emissions testing, trying to qualify a design, only to have to
redesign it and requalify it after you have made a large
production run that need to be scrapped, just because of some
stupid idiot like the guy at the board house in this particular
case, who probably just didn't have the right material in
stock, or worse yet, had some extra material he just wanted to
get rid of. This guy really does need to be called on the
carpet.
I don't want this idiot making any boards for me, and I really
don't think that you want him making any boards for you.
I want to know just who he is and who he works for, so that I
do not make the mistake of sending him any business.
This kind of incompetence is a problem in our industry, and we
will never correct it by ignoring it or sugar coating it.
Yes, incompetence is the correct word.
I am sorry if I am calling a spade a spade.
Why am I making an issue out of this? Because the average
designer does not know what a monumental blunder something like
this is.
This is important, and it is important that anyone who is out
there designing boards knows that it is important, even if he
does not totally understand it.
That's why it should not be sugar coated.
That's why I am being so polite.
I am sorry if you are offended, but once again, this is not a
joke.
JaMi
* * * * * * * * * *
----- Original Message -----
From: Eric Bonatti
To: [log in to unmask]
Sent: Friday, June 06, 2003 4:53 PM
Subject: Re: [DC] Core thickness/emissions
Oh, come on JaMi, don't sugar-coat it. Tell us like you
really feel.
Eric
----- Original Message -----
From: JaMi Smith
To: [log in to unmask]
Sent: Friday, 06 June 2003 19:26
Subject: Re: [DC] Core thickness/emissions
The quick answer is: Yes! Absolutely! Unquestionably!
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