[SI-LIST] Re: Off Topic Question
- From: "Ruturaj Pathak" <Ruturaj.Pathak@xxxxxxx>
- To: "'Si-List' (E-mail)" <si-list@xxxxxxxxxxxxx>
- Date: Thu, 7 Nov 2002 13:56:56 -0800
I definitely agree with Thomas.
This is a very generic question because there are a lot of parameters =
affecting the design.
Time to market, specification complexity & changes down the road play a =
major role. Sometimes we have to get the first revision out just to show =
a piece of Hardware.
For our company it varies and we generally get the production build at =
the rev2 phase of the design. Regards,
Ruturaj Pathak
Sr. HW Design Engineer
EFI Corporation
-----Original Message-----
From: Jackson, T L [mailto:t.l.jackson@xxxxxxxx]
Sent: Thursday, November 07, 2002 1:32 PM
To: 'breams@xxxxxxxxxxxxxx'; 'Si-List' (E-mail)
Subject: [SI-LIST] Re: Off Topic Question
In my experience,
If one has a firm description of what the design is supposed to do
and
if one is willing to put the effort into serious modeling and design =
checks
before starting fabrication and assembly,
one can go to production on the first layout. This has the disadvantage =
of
taking the longest time until there is something tangible that =
Management
and/or Marketing can show to potential customers.
In the real world, someone has to make the tradeoff between the amount =
of
modeling performed before fabrication versus the cost of debugging and
respinning a design. Somewhere between the two extreme of "model =
everything
in excruciating detail" and repeated "Build and Test" is the lowest =
cost,
fastest path to production. The hard part is figuring out where this =
point
is for a given design, staff, toolset, company, etc. All this assumes =
one
is not trying to hit a moving target, i.e. the functions, performance, =
cost
target, etc. are not changing during development.
Personally, I have gotten it right on the first time more than once and
never took more than two.
TJ
Thomas L. Jackson, PE
Senior Staff System Engineer
L1-50, Remote Sensing Systems Engineering
Missiles and Space Operations
Lockheed Martin Space Systems Company
telephone: (408) 742-2013
facsimile: (408) 742-7701
location: B149/E2
-----Original Message-----
From: Bill Reams [mailto:breams@xxxxxxxxxxxxxx]
Sent: Thursday, November 07, 2002 1:01 PM
To: 'Si-List' (E-mail)
Subject: [SI-LIST] Off Topic Question
Ladies and Gentlemen,
I have a question that is off topic for this list. However, as we all =
=3D
work at companies ranging from medium tech to very high tech, this =3D
seemed a good source for a non-scientific poll.
For your "typical" projects, how many circuit board revisions does it =
=3D
take to go from the block diagram stage to full production release?
I know that in the perfect world, everyone would answer "One board, my =
=3D
first prototype is always perfect." But we've probably all seen the =3D
project where we're sent off to design a left-handed widget and =3D
eventually deliver the flux capacitor that they really wanted - but only =
=3D
after a large number of revisions and redesigns because they couldn't =
=3D
figure out how to ask for what they wanted. What I'm interested in is =
=3D
not the extreme revision numbers, but the typical number of revisions =
=3D
for typical projects. And please do include all revisions for DFM, DFT, =
=3D
EMC/EMI related modifications.
Thanks for your responses.
Bill
_______________________________________
| |
| Bill Reams - Sr. Hardware Engineer |
| 512-928-7201 (direct) |
| 512-349-0300 (Main) |
| breams@xxxxxxxxxxxxxx (e-mail) |
|______________________________________|
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