Used to buzz WAY too often, that's why I haven't buzzed in 'bout 15 years :) Durn bees :) -- George Patrick Tektronix, Inc. Central Engineering, PCB Design Group P.O. Box 500, M/S 39-512 Beaverton, OR 97077-0001 Phone: 503-627-5272 Fax: 503-627-5587 http://www.tektronix.com <http://www.tektronix.com> http://www.pcb-designer.com It's my opinion, not Tektronix' -----Original Message----- From: Jay DeKing [mailto:[log in to unmask]] Sent: Thursday, December 11, 2003 21:47 PM To: [log in to unmask] Subject: [DC] OT: Re: [DC] Manufacture adjusting Gerber's This post is definitely a bit off topic, but I guess I'm spoiled from the PADS listserver ... which is notoriously off-topic on a regular basis ... I think that I should re-subscribe to this list at my work e-mail address, so I can read it during the day. I always seem to finally get around to reading the DC list at about 11 or 12 pm, when I have a bit of a buzz on and am getting ready for bed. It just doesn't do much good at that point ;-) I'm scanning through it right now, knowing that I should understand what's going on, but it just isn't sinking in! Sorry for the OT post. This list is always so professional, and I like it that way! I can't believe that 10 years ago I used to work with a buzz on every day. At the time, I was *sure* that it gave me a creative edge. Ugh. (By the way, if anybody wants to contribute any comments about that, please send to me off-list. I don't want to contaminate DC with that kind of thread. One OT post is enough.) Jay On Wed, 2003-12-10 at 11:39, Kowalewski, Andy wrote: > It's to do with the plating of the barrel in a multilayer board. > > When the hole is drilled, the external surfaces have complete copper > coverage and so the annular ring isn't evident until after imaging and > etching. Hence you can add the thickness of the plating to the pad size > for an annular ring requirement. > > On the inner layers, imaging and etching have already been completed so > when the hole is drilled, it needs to 'see' enough copper around the > hole so that the plating of the barrel makes good contact to the > innerlayer pad. That hole size is the drilled hole, but the final hole > size is the one specified by the designer and relies on an oversize > drilled hole to be plated up. So the annular ring is specified 'worst > case', which is before plating. > > > Andy K. > Sychip Inc > Office (972) 202 8852 > > -----Original Message----- > From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Stan > Radzio > Sent: Wednesday, December 10, 2003 10:34 AM > To: [log in to unmask] > Subject: Re: [DC] Manufacture adjusting Gerber's > > Gary, > I was following you right up to the point where you said "for > inner layers". I don't mind looking like an idiot asking questions that > are obvious to everyone else. Could you explain why you are using the > drill hole size versus the finished hole size on inner versus outer > layers? Said another way: what is the manufacturing process that you > are accommodating with this design decision? > > Thanks, > -Stan > > > -----Original Message----- > From: Gary Ferrari [mailto:[log in to unmask]] > Sent: Tuesday, December 09, 2003 5:12 PM > To: [log in to unmask] > Subject: Re: [DC] Manufacture adjusting Gerber's > > > Ted, > > The board fabricator always drills with a larger drill bit to compensate > for shrinkage of the laminate. This is why the designer uses the drilled > hole size when calculating lands for inner layers. The finished hole > size is used for calculating outer layer land sizes. > > The board fabricator is not requred to automatically adjust > inappropriate spacing. They usually will contact the designer and > explain the problem. That is, if you use a decent board fabricator. > > Regards, > > Gary > > ------------------------------------------------------------------------ > --------- > 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 set a vacation stop for delivery of DesignerCouncil > send: SET DesignerCouncil NOMAIL 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 > 847-509-9700 ext.5315 > ------------------------------------------------------------------------ > --------- > > ------------------------------------------------------------------------ > --------- > 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 set a vacation stop for delivery of DesignerCouncil send: SET > DesignerCouncil NOMAIL > 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 847-509-9700 > ext.5315 > ------------------------------------------------------------------------ > --------- > > ---------------------------------------------------------------------------- ----- > 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 set a vacation stop for delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL > 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 847-509-9700 ext.5315 > ---------------------------------------------------------------------------- ----- -- "Whether it's Osama bin Laden, Saddam Hussein or Kim Jong Il, much of today's news is dominated by pricks." - Jon Stewart, "The Daily Show" ---------------------------------------------------------------------------- ----- 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 set a vacation stop for delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL 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 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- 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 set a vacation stop for delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL 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 847-509-9700 ext.5315 ---------------------------------------------------------------------------------