The electrons pile up on the inside of the corner, just like Schumacher and Alonso. Brian Wayne Thayer wrote: > I have heard and read about a phenomenon which sounds kind of scientific > but which I have never seen. This is that if you have an acute angle in > an etched circuit trace it will "trap" etchant and thus over-etch. This > is actually mentioned in Joseph Fjelstad's flex circuit book people have > been talking about. > > I've done lots of etching and haven't seen this effect at all. > Actually, my experience has been that inside corners under-etch, not > over-etch, which I presume to be the result of the same hydrodynamic > phenomenon quoted by the proponents of the over-etch theory: Surface > tension causes the etchant to stick in the corners. This "stuck" > etchant quickly becomes saturated with copper, and the etching process > stalls because not as much hot, high pressure etchant can get to the > affected area. > > Not that I intentionally design circuits with acute angles in the > traces--I think they are non-optimal for other reasons, but I want to > make sure I'm doing the right thing for the right reason. > > Wayne Thayer > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > 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.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 > ----------------------------------------------------- > -- http://www.cypenv.org Cyprus environment/energy http://www.cypenv.org/worldenv World environment/energy http://www.cypenv.org/weather Cyprus weather http://www.cypenv.org/smf/index.php Environment/energy forums http://groups.yahoo.com/group/cypnature/ Cyprus nature forum --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------