(((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 -----------------------------------------------------