Hi David, This would depend upon your board requirements. Where a board basically has everything within its borders as a `component' in the system (and thus requires to be `connected to something') then yes, drawing a `fat' keepout track on top the mechanical board outline is a simple and effective way of achieving the desired result. Where, however, a board has, for example, some fixing holes that are not to be connected to anything (lets say we are mounting in a metal enclosure and require isolation from the case) then it is easier to draw a separate keepout line inside the board edge which can then deviate away from the board edge to come `inside' an item that you don't want connected. I also find that with some edge connectors such as DB9 that been able to move the keepout line is useful. I am sure there are workarounds for all of this but at the end of the day I have just got into the habit of creating a board outline, jumping to the Keepout layer and tracking inside the board outline. I then find it relatively easy to start tweaking the keepout line. This would be only marginally complicated with your approach in that you would have to probably start adjusting the `fatness' as well.
I personally find that minimising the number of rules I have and using the `pcb layers' as much as possible tends to make the board more readable by others (a requirement at the place I work). We have, in the past had to work on customer (project) files that they have supplied and have been burnt a couple of times when we have found that a rule has not come across with the project or that an internal rule has remained active and affected the board (most notably with polygon planes and arcs) Best Regards (Mr) Laurie Biddulph Mobile: 0400 257 645 Elby Designs ABN: 70 022 727 605 http://www.elby-designs.com This e-mail and any files transmitted with it are confidential and intended for the addressee only. If you are not the addressee you may not copy, forward, disclose or otherwise use it, or any part of it, in any form whatsoever. If you have received this e-mail in error please notify the sender and ensure that all copies of this e-mail and any files transmitted with it are deleted. Any views or opinions represented in this e-mail are solely those of the author and do not necessarily represent those of Elby Designs. Although this e-mail and its attachments have been scanned for the presence of computer viruses, Elby Designs will not be liable for any losses as a result of any viruses being passed on. ----- Original Message ----- From: David Cary To: Protel EDA Discussion List Sent: Friday, May 19, 2006 11:30 AM Subject: Re: [PEDA] Fwd: 99SE PCB Component gone afar. Dear Protel users, > From: Laurie Biddulph <[EMAIL PROTECTED]> ... > Working in the pcb assembly world and also designing my own boards we strongly recommend customer to place a Keepout line approximately 2mm inside the board outline. There are certainly several good reasons to keep components 2 mm inside the board outline. In Protel, rather than draw a keepout line 2 mm inside the board outline, I find it more convenient to draw the keepout line exactly on the board outline, but with "fat traces" 4 mm wide. Both techniques have the same effect, right? (OK, what I really do is make the keepout traces 0.120 inch wide -- keeping traces 0.060 inch back from the edge. Then I add a rule to force a keepout-component gap of 0.040 inch, which has a net effect of keeping components 0.100 inch back from the edge.) -- David Cary http://protel-users.org/ http://en.wikipedia.org/wiki/PCB_layout_guidelines ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[email protected] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[email protected] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[email protected] ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[email protected] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[email protected] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[email protected]
