TECHNET Archives

September 2006

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Franklin D Asbell <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Franklin D Asbell <[log in to unmask]>
Date:
Thu, 28 Sep 2006 15:22:57 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (242 lines)
(laughing)

IMHO AABUS S/B R/W "as agreed"


Franklin D Asbell
1311 Carnation Drive
Lewisville, Texas 75067
972-221-1178 - home
214-682-5625 - cellular
[log in to unmask]
www.asbell.net for a different perspective on quality systems implementation

Tip of the day: Electronic forms and records save time and resources even
when your initials are required, ask us how to digitize your quality
management system today.


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Whittaker, Dewey (EHCOE)
Sent: Thursday, September 28, 2006 2:48 PM
To: [log in to unmask]
Subject: Re: [TN] Build Structure Communication

As long as you're espousing philosophical tips, dump the UOS; keep the
period; add new sentence stating "Deviations to this requirement shall be
AABUS( as agreed between user and supplier)". I get royalties for this now
that I got the IPC to legally recognize this in IPC-T-50.
Dewey

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jeffrey Bush
Sent: Thursday, September 28, 2006 12:05 PM
To: [log in to unmask]
Subject: Re: [TN] Build Structure Communication

All Dimensions are finished UOS.

Plato

Jeffrey Bush
Director, Quality Assurance and Technical Support VERMONT CIRCUITS
INCORPORATED
           76 Technology Drive - POB 1890
              Brattleboro, Vermont 05302
                Voice - 802.257.4571 ext 21
                    Fax - 802.257.0011
                       <http://www.vtcircuits.com/>


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Dan Skweres
Sent: Thursday, September 28, 2006 11:26 AM
To: [log in to unmask]
Subject: Re: [TN] Build Structure Communication

Frank,
So you're saying you specify starting copper weight and the finished weight
doesn't matter? I would think stating a minimum copper weight would get you
closer to what you want. If you were to specify H oz.
starting copper I agree you would have at least H oz. copper after plating
but as you stated various suppliers could in fact supply you with different
copper thicknesses depending on their processes. I realize IPC does break it
down (starting foil, class 1,2,3  plating
thickness etc.)  but it doesn't guarantee anything.   I guess the quote
was right... It all does depends.
Dan S

>>> [log in to unmask] 09/28/06 10:03AM >>>
Phillip,
To quote the great one "it depends"

What are you trying to achieve?
What is critical to your design?
How bad do you want to keep cost down?


Once you have answered these questions and probably a few dozen more you can
start to develop a plan to document PCB construction.
We do as follows with reasoning included:

1. Copper weight is always stated as starting. This allows us to ensure we
have a minimum copper weight for our current requirements and are not
reliant on various supplier plating processes. Also any additional plating
helps to derate our current calculations. And we can plan our designs to use
standard copper weights and minimize cost and lead issues.

2. Dielectric thickness needs to be determined according to usage. For a
pure digital design a minimum dielectric thickness is enough but for
controlled impedance we specify a fixed dielectric and thickness.
Presently there are about 20 different standard stackups in my system
ranging from 2 to 10 layers.

We have designs that use .004 min dielectric layers with foil lamination and
designs that have set outer layer thickness that requires book build
processes, some are pure cheap FR-4 and others are RF Exotics, so we need to
have a large number of standard stackups. You may find you need lots of
standards or may get lucky and only have a couple.

Once you classify the design types you are producing you can then develop
the standard stackups you want your suppliers to use. Remember to first talk
to your suppliers and see if you can work concurrently to find the best
match and then to keep it as simple as possible to help minimize your costs.

Hope it helps,
FNK

Frank N Kimmey CID+
Principal PCB Designer
PCB Programs
Powerwave Technologies Inc
Office 916-941-3159
Fax 916-941-3195
Mobile 916-670-0645
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Anslow, Phillip
Sent: Thursday, September 28, 2006 12:46 AM
To: [log in to unmask]
Subject: [TN] Build Structure Communication

Dear Fellow TechNetters,

Would you please share how you communicate your PCB build structures to PCB
fabricators, or, if you are a fabricator, how those which are easiest to
understand are presented to you.

For copper, is it best to quote (i) Nominal start weight or thickness,
(ii) minimum finished thickness to IPC-2221A tables before and/or after
plating if applicable?

For dielectric thickness, (i) specify value, (ii) give range (iii) leave
open?

Your advice and expertise is greatly appreciated.

Many thanks and regards,

Phil



********************************************************************
This email and any attachments are confidential to the intended recipient
and may also be privileged. If you are not the intended recipient please
delete it from your system and notify the sender.
You should not copy it or use it for any purpose nor disclose or distribute
its contents to any other person.
********************************************************************

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e To
unsubscribe, send a message to [log in to unmask] with following text in the
BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or
(re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per
day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information,
or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e To
unsubscribe, send a message to [log in to unmask] with following text in the
BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or
(re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per
day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information,
or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
-----------------------------------------------------




---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text
in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text
in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------

ATOM RSS1 RSS2