If it is important to the design function state it down to the details needed for performance. If you just need a 8 layer, 1/16 board, FR4 with 1 oz copper, this fits neatly into a Note 2 and allow the fabricator to build the unit as economically and IAW there process needs. You Note 1 for specification will cover you on how the package should perform. The disadvantage of getting to specific where it is not needed becomes an issue from supplier to supplier. You talk to Joe Circuits and they use a 3070 and 106 glass and Short Circuits uses just 2116 and 1080 - this becomes a real issue when you become that specific. On the other hand when your need a .015" H/2 6010LM bonded to a .030" H/1 RT3206 with 3xRO4450 then this becomes a needed part of you construction detail. In this case include all the specifics on tolerances, etc. 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 Anslow, Phillip Sent: Thursday, September 28, 2006 3:46 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 -----------------------------------------------------