Hi, Many years ago(+/- 6 years) we designed 14 layers into a 1.6 thick pcb using 1 ounce copper on the internal layers, sadly the manufacturing houses experienced "copper spreading" on the internal layers. The explanation provided was that squeezing 14 layers into 1.6mm pcb was causing the internal layer copper to spread sideways. We were than advised to consider 0.5 ounce(17u) copper. We changed to 0.5 ounce and NEVER had a problem since. Using that as an argument I would than assume using 2 ounce copper could have made that pcb almost impossible to manufacture, than again it also depends on the number of layers. regards Billy Bharath -----Original Message----- From: Sanchez-Benavides Erika [mailto:[log in to unmask]] Sent: Wednesday, April 06, 2005 2:12 PM To: [log in to unmask] Subject: [DC] PCB TECHNOLOGY (2 oz copper) Hello all, One of our PCB suppliers came out with a PCB design that have 2 ounces of copper on all layers. Until now we have worked with PCB that have 2 ounces of copper only on the exterior layers, and only one ounce of copper on the interior layers. We do not have experience working with PCBs with 2 ounces of copper on all the layers. Would you mind helping us to gain more knowledge regarding these PCBs? Are there any risks associated with this design: thermal events, concerns, things that we should be aware of? Thanks in advance, .......................................................... Kind regards Erika E. Sanchez PCB Designer Siemens VDO Internet: http://www.siemensvdo.com ---------------------------------------------------------------------------- ----- DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF DesignerCouncil. To temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL) Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF DesignerCouncil. To temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL) Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------