IMO, I think this is a holdover from the "old days", although I have no studies or evidence handy to back up my opinion. I still think using acute angles is poor design practice, but from a practical standpoint I'm not sure it makes a difference anymore. My $.02, Jason Roetz, CID+ Master Designer Electrical Group, Industrial Controls Division 4201 North 27th Street Milwaukee, WI. 53216 Telephone: 414-449-6397 Fax: 414-449-7319 [log in to unmask] http://www.eaton.com/ -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Cote, Clint (GE Intelligent Platforms, US) Sent: Tuesday, January 11, 2011 11:53 AM To: [log in to unmask] Subject: [TN] Acute Angles We have a bunch of old references to avoid acute angles when routing traces. The acute angle would become an acid trap and continue etching the trace until it reduces it or breaks it completely. Is this still an issue with modern chemistry and cleaning? Do acute angles present a long term reliability issue? Are there any studies or evidence that I can reference? Thanks, Clint Cote ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- 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.aspx?Pageid=E-mail-Forums for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- 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.aspx?Pageid=E-mail-Forums for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------