(laughing) IMHO AABUS S/B R/W "as agreed" Franklin D Asbell 1311 Carnation Drive Lewisville, Texas 75067 972-221-1178 - home 214-682-5625 - cellular [log in to unmask] www.asbell.net for a different perspective on quality systems implementation Tip of the day: Electronic forms and records save time and resources even when your initials are required, ask us how to digitize your quality management system today. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Whittaker, Dewey (EHCOE) Sent: Thursday, September 28, 2006 2:48 PM To: [log in to unmask] Subject: Re: [TN] Build Structure Communication As long as you're espousing philosophical tips, dump the UOS; keep the period; add new sentence stating "Deviations to this requirement shall be AABUS( as agreed between user and supplier)". I get royalties for this now that I got the IPC to legally recognize this in IPC-T-50. Dewey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Jeffrey Bush Sent: Thursday, September 28, 2006 12:05 PM To: [log in to unmask] Subject: Re: [TN] Build Structure Communication All Dimensions are finished UOS. Plato 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 Dan Skweres Sent: Thursday, September 28, 2006 11:26 AM To: [log in to unmask] Subject: Re: [TN] Build Structure Communication Frank, So you're saying you specify starting copper weight and the finished weight doesn't matter? I would think stating a minimum copper weight would get you closer to what you want. If you were to specify H oz. starting copper I agree you would have at least H oz. copper after plating but as you stated various suppliers could in fact supply you with different copper thicknesses depending on their processes. I realize IPC does break it down (starting foil, class 1,2,3 plating thickness etc.) but it doesn't guarantee anything. I guess the quote was right... It all does depends. Dan S >>> [log in to unmask] 09/28/06 10:03AM >>> Phillip, To quote the great one "it depends" What are you trying to achieve? What is critical to your design? How bad do you want to keep cost down? Once you have answered these questions and probably a few dozen more you can start to develop a plan to document PCB construction. We do as follows with reasoning included: 1. Copper weight is always stated as starting. This allows us to ensure we have a minimum copper weight for our current requirements and are not reliant on various supplier plating processes. Also any additional plating helps to derate our current calculations. And we can plan our designs to use standard copper weights and minimize cost and lead issues. 2. Dielectric thickness needs to be determined according to usage. For a pure digital design a minimum dielectric thickness is enough but for controlled impedance we specify a fixed dielectric and thickness. Presently there are about 20 different standard stackups in my system ranging from 2 to 10 layers. We have designs that use .004 min dielectric layers with foil lamination and designs that have set outer layer thickness that requires book build processes, some are pure cheap FR-4 and others are RF Exotics, so we need to have a large number of standard stackups. You may find you need lots of standards or may get lucky and only have a couple. Once you classify the design types you are producing you can then develop the standard stackups you want your suppliers to use. Remember to first talk to your suppliers and see if you can work concurrently to find the best match and then to keep it as simple as possible to help minimize your costs. Hope it helps, FNK Frank N Kimmey CID+ Principal PCB Designer PCB Programs Powerwave Technologies Inc Office 916-941-3159 Fax 916-941-3195 Mobile 916-670-0645 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Anslow, Phillip Sent: Thursday, September 28, 2006 12:46 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 ----------------------------------------------------- --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------