Joe, Wayne, and others...

  A couple of words about ammoniacal etch which might help shed some light on the situation.

  90+% of the pcb fabricators control ammoniacal etch using only density (Baume').

  This was adequate when we called 10 mil line and space "fine lines", but really is not adequate for today's world...

  Think about the fact that Cupric etch has three conditions which are monitored:

  Metal content (By density)
  Acidity (Usually by conductivity)
  Cuprous Content (By ORP)

  If you were going to control ammoniacal with the same precision you would control by the following

  Metal Content (By density)
  pH (Comparable to Acidity in the Cupric etch)
  Cuprous Content (which is controlled by air flow through the chamber)

  So, in many ways the ammoniacal etch today could be considered to be operating on luck.   The system works best when it is used continuously.  The system is pushed to its limits when operated intermittently.

  Rudy Sedlak
  RD Chemical Company


---------------------------------

---------------------------------------------------
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
-----------------------------------------------------
Yahoo! Messenger with Voice. Make PC-to-Phone Calls to the US (and 30+ countries) for 2¢/min or less.