Ken, Your wash system is tracking the resistivity or conductivity of your rinse water and your filter plant is taking care of such contaminants that are entering the process. The question is how much contamination is on the assembly, and has it all been removed? I doubt that you can accurately maintain the amount of contamination that is being applied to your assembly both in your process and that of your PC Fab shop. It is therefore a good idea to conduct regular ROSE tests to ensure that your process is always under control. The sampling rate to achieve that is another subject that should be addressed. Graham Naisbitt ------------------------------------------------------------------------------ ---- [log in to unmask] Concoat Ltd Tel: +44(0)1276691100 Alasan House, Albany Park Fax: +44(0)1276691227 Camberley GU15 2PL UK -----Original Message----- From: TechNet On Behalf Of Ken Patel Sent: Thursday, November 13, 1997 10:26 PM To: [log in to unmask] Subject: [TN] Do we really need ionic contamination measurement equipment? SMT/Wave Process Expert, If the conductivity of the DI water of wash machine is maintained along with good maintenance of the wash machine, do we still feel that it is always or must to have ionic contamination measurement equipment like one of that Alphametal makes? I am really interested in pros and cons of having such system from need point of view rather than sales pitch (to show to prospective customers). Re, Ken patel ______________________________________________________ Ken Patel Phone: (408) 490-6804 575 Cottonwood Dr. Fax: (408) 490-6859 Milpitas, CA 95035 Beeper: (888) 769-1808 ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ############################################################## ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################