Bill, I fall into the same camp as Peter, I like the non-functional pads for additional hole wall support. If however you have a high layer count board with heavy (>1oz) Cu then hole quality can (probably will) be affected to some degree by the retention of the NFP's. Para 9.1.4 in IPC 2222 refers Regards Ian Fox Goodrich Engine Control Systems -----Original Message----- From: [log in to unmask] [mailto:[log in to unmask]] Sent: 27 March 2003 05:43 To: [log in to unmask] Subject: Re: [TN] non functional pad removal No specs, Bill, but some experience that may help. "Non-functional pads", as you probably know tend to be generated as an inherent feature of routing packages - you specify through-holes and associated pads for the outer layer of a PCB, and that information gets copied throughout the layer stack to save the router having to re-specify them for every layer that needs connection to the barrel. Thus there are plenty of internal pads that have no traces attached to them on certain layers, and these are the 'non-functional' ones. Some fab houses like to remove these pads, especially in fine line boards, to reduce any risk of short circuits occurring between them and neighbouring traces or other electrically powered features. I wonder how good the etching processes are whenever I get a removal request from a fab house. There are usually options in Gerber readers used by fab houses to remove these pads at the press of a button, but the customer should be given the option of retaining or removing the pads if there is not other instruction one way or the other. I specify not to remove N-F pads on my PCB drawings. Keeping or removing N-F pads is subjective. Me, I prefer to keep them, as I believe that they help to support the barrel plating against resin recession and hole pull-away effects, should there be any, but others I respect are quite happy to get rid of them. I disagree with them naturally, but it makes for healthy debate. Peter Bill Decray <[log in to unmask]> 27/03/2003 04:33 AM Sent by: TechNet <[log in to unmask]> Please respond to "TechNet E-Mail Forum."; Please respond to Bill Decray To: [log in to unmask] cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) Subject: [TN] non functional pad removal Hello fellow TechNet Guru Does anyone have or know off any specifications that talk about removal of non functional pads and what effects it has on a finished circuit boards if any Highest Regards, William W. 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