Here's another what we do: As a rule any hole beneath .030" is used as a via, and therefore not soldered to. We the add to our drill table the following: 1. Holes smaller than 30 mils show nominal finished size, but no tolerance. 2. Added column shows drill size (nominal +.005") +/-.001 (allows 2-3 drill availability) for any hole without tolerance. 3. Add a note stating - HOLES WITH DEFINED DRILL SIZES MAY BE PLATED SMALLER THAN NOMINAL. This allows us to define outer barrel diameter, follow our stated minimum .001" hole wall thickness, and compensate for plating variance between small holes (<.030") and large holes (>.100"). Our suppliers seem to be very comfortable with this, giving us high yields and we don't have hole issues at assembly. Just another way to achieve the need. 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 Karl Hunsinger Sent: Friday, April 27, 2007 11:42 AM To: [log in to unmask] Subject: Re: [TN] "plated shut vias" Our drawings almost always have a tolerance associated for vias. As Ramon just stated, we add a "plating factor" to the specified hole size to obtain the drill size. The expectation is to finish at the nominal (middle of the tolerance) hole size. Karl -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Dehoyos, Ramon Sent: Friday, April 27, 2007 2:32 PM To: [log in to unmask] Subject: Re: [TN] "plated shut vias" Agreed, We just went through such an exercise and the conclusion was that the specified hole size was the final hole size. A 6, 7, 8 or 5 mils were added to find the drill size. Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Smith, Richard Sent: Friday, April 27, 2007 10:05 AM To: [log in to unmask] Subject: Re: [TN] "plated shut vias" I don't disagree but, unless I'm behind the times which is entirely possible, the IPC used to promote the practice of specifying all plated hole sizes as finished permitting the manufacturer to select the appropriate drill. I'm not implying this is the best practice, but on the other hand I've not seen a via reliability issue attributable to the finished via hole tolerance on the drawing. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier Sent: Thursday, April 26, 2007 3:23 PM To: [log in to unmask] Subject: Re: [TN] "plated shut vias" Hi All, Vias should never be specified in terms of finished hole size (there is no functional need for any specific finished hole diameter), but in terms of drilled hile diameter, because that determines all kinds of things important to the reliability of the via interconnect structure. Werner ************************************** See what's free at http://www.aol.com. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 15.0 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 15.0 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 15.0 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 15.0 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 -----------------------------------------------------