This could also be an issue of inventory/material availability. The fabricator may not have 1 oz copper in stock. Another issue is the use of electrolytic nickel/gold. There are galvanic etching problems with the combination of Cu/Ni/Au as well as overhang/leaf of the gold plating. The more you have to etch through the more this can become a problem. 0.5 oz copper in place of 1 oz makes sense in this application. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Cal Driscoll Sent: Wednesday, July 28, 2004 5:20 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 -----------------------------------------------------