TECHNET Archives

July 2004

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 <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Wed, 28 Jul 2004 15:31:46 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (157 lines)
(((nodding my head in agreement)))


----- Original Message -----
From: "Jeffrey Bush" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, July 28, 2004 2:14 PM
Subject: [TN] FW: [TN] 1oz Copper vs. .5 oz Copper


This is not matter of capability, but rather a matter of good design
practice for 5 mils lines and less.  Unless the current capacity is an
issue  at 5 mil lines, and you the 2 oz finished weight, the starting
weight should be 0.5 oz.  Most reputable shops can etch 2+ oz foils down
to 4 mil lines or less, but when this design is not needed it should not
be applied.  Many designer unknowing of the PCB process have simulated
the signal using the 1.4 mil thickness, not understanding the surface is
going to get plated with the holes and improve on the drawing
requirement. 1 oz copper on a drawing is a finished value OOS.

I will present to you that the shop that requested the 0.5 oz foil was
more "on-the-ball" then the shop ignoring a process improvement
opportunity just keeps using 1 oz foil.



Jeffrey Bush
Director, Quality Assurance and Technical Support

                          76 Technology Drive - POB 1890
                             Brattleboro, Vermont 05302-1890
                                Tel. 802.257.4571.21 Fax. 802.257.0011
                                    [log in to unmask]
                              http://www.vtcircuits.com



-----Original Message-----
From: James Hofer [mailto:[log in to unmask]]
Sent: Wednesday, July 28, 2004 12:52 PM
To: TechNet E-Mail Forum.; Jeffrey Bush
Subject: Re: [TN] 1oz Copper vs. .5 oz Copper


If the new shop has issues etching 1 oz foil with line widths below 6 or
7 mils than again they must be carefully looked at.

James Hofer
Director of Operations
Accurate Circuit Engineering
3019 S. Kilson Dr.
Santa Ana Ca. 92707-4202
714-546-2162 work
714-473-6127 cell
[log in to unmask]
----- Original Message -----
From: "Jeffrey Bush" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, July 28, 2004 7:05 AM
Subject: Re: [TN] 1oz Copper vs. .5 oz Copper


This is likely a capability issue - getting down below 6 or 7 mil lines
and spaces the starting weight (what you are etching) of the foil needs
to be less than 1 oz for good line resolution.  Thicker conductors in
denser geometries create a host of issues from conductor definition to
soldermask coverage to ID screen legibility, etc.


Jeffrey Bush
Director, Quality Assurance and Technical Support

                          76 Technology Drive - POB 1890
                             Brattleboro, Vermont 05302-1890
                                Tel. 802.257.4571.21 Fax. 802.257.0011
                                    [log in to unmask]
                              http://www.vtcircuits.com



-----Original Message-----
From: Cal Driscoll [mailto:[log in to unmask]]
Sent: Wednesday, July 28, 2004 8:20 AM
To: [log in to unmask]
Subject: [TN] 1oz Copper vs. .5 oz Copper


Hi All-

One of our PCB designers came to us with a recommendation from our Bare
Board fab house- We typically use 1 oz copper and the fab house is
asking us to use .5 oz copper and build it up to 1 oz.

Since I am not a designer, so I would like some input from TechNet on
this type of practice.

Facts:
99% of our boards are used in Telecommunications products
Most of our boards have QFP's in the 12 mil range
Typically most of our boards have Gold pads/finish


Thanks,
cal

---------------------------------------------------
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
847-509-9700 ext.5315
-----------------------------------------------------

---------------------------------------------------
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 847-509-9700 ext.5315
-----------------------------------------------------

---------------------------------------------------
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
847-509-9700 ext.5315
-----------------------------------------------------

---------------------------------------------------
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 847-509-9700 ext.5315
-----------------------------------------------------

ATOM RSS1 RSS2