YOUR SUCH A STAR..... ______________________________ Reply Separator _________________________________ Subject: Re: Non-Functional Pads? Author: [log in to unmask] at internet_gateway Date: 10/17/95 10:58 AM Received: by ccmail from chopin.multek.com >From [log in to unmask] X-Envelope-From: [log in to unmask] Received: from miso.wwa.com by chopin.multek.com with SMTP (1.37.109.4/16.2) id AA27412; Tue, 17 Oct 95 12:00:59 -0700 Resent-Date: Tue, 17 Oct 95 10:58:28 PST Received: from ipc by miso.wwa.com with uucp (Smail3.1.28.1 #8) id m0t5HHm-000iOJC; Tue, 17 Oct 95 14:02 CDT Received: by ipchq.com (Smail3.1.28.1 #2) id m0t5GIj-0000HBC; Tue, 17 Oct 95 12:59 CDT Old-Return-Path: <miso!multek.com!acochrane> Date: Tue, 17 Oct 95 10:58:28 PST From: "COCHRANE, ALAN" <[log in to unmask]> Encoding: 79 Text Message-Id: <[log in to unmask]> To: [log in to unmask] Subject: Re: Non-Functional Pads? Resent-Message-Id: <"eBEyS1.0.n88.zx-Wm"@ipc> Resent-From: [log in to unmask] X-Mailing-List: <[log in to unmask]> archive/latest/1388 X-Loop: [log in to unmask] Precedence: list Resent-Sender: [log in to unmask] Kevin, I would think that if a vendor were to remove the non functional pads then they would let the end user know. As you know I feel that non functional pads are VERY benificial in the fabrication of boards. 1. More retained surface copper = improved or better controlled dimensional stability 2.Complete pad stack to verify via x-ray, drill alignment 3.Complete pad stack to verify registration/misregistration via x-section. 4.Copper to minimize the amount of drill splay specificly on thick boards. 5. Additional copper to help remove epoxy build-up in the drill flutes 6. Extra interconnects to help deliniate the amount of z-axis expansion and the stress on the interconnects. The only possible negative that I see is on some high speed designs where x-talk/coupling is a factor. If we remove the pads we can increase the space from drill hole to trace. I have heard alot of people say "why have more potential for shorts if I don't need to." I would say to them "get a better AOI system" Regards, Alan B. Cochrane Director of New Technology Multek Inc. ______________________________ Reply Separator _________________________________ Subject: Non-Functional Pads? Author: [log in to unmask] at internet_gateway Date: 10/17/95 10:04 AM Received: by ccmail from chopin.multek.com >From [log in to unmask] X-Envelope-From: [log in to unmask] Received: from mx.smtp.psi.net by chopin.multek.com with SMTP (1.37.109.4/16.2) id AA27280; Tue, 17 Oct 95 09:57:45 -0700 Received: from miso.wwa.com by mx.smtp.psi.net (8.6.12/SMI-4.1.3-PSI) id MAA13812; Tue, 17 Oct 1995 12:49:28 -0400 Resent-Date: Tue, 17 Oct 1995 12:49:28 -0400 Received: from ipc by miso.wwa.com with uucp (Smail3.1.28.1 #8) id m0t5FBj-000iKAC; Tue, 17 Oct 95 11:48 CDT Received: by ipchq.com (Smail3.1.28.1 #2) id m0t5Dn9-0000GlC; Tue, 17 Oct 95 10:18 CDT Old-Return-Path: <miso!eag.unisysgsg.com!KTHORSON> From: "Thorson, Kevin J @EAG" <[log in to unmask]> To: "'IPC Technical Forum'" <[log in to unmask]> Subject: Non-Functional Pads? Date: Tue, 17 Oct 95 10:01:00 CST Message-Id: <[log in to unmask]> Encoding: 10 TEXT X-Mailer: Microsoft Mail V3.0 Resent-Message-Id: <"k-ryW2.0.jt2.LbyWm"@ipc> Resent-From: [log in to unmask] X-Mailing-List: <[log in to unmask]> archive/latest/1384 X-Loop: [log in to unmask] Precedence: list Resent-Sender: [log in to unmask] The design guides for MIL-STD-275 and IPC-D-275 require non-functional pads on all layers of a multilayer PWB. Can manufacturers remove them an their judgment? If anyone knows the verse and script, that would be great. Thank you in advance, Kevin Thorson Loral Defense Systems - Eagan