It is also often important to remove as much water from the surface as is possible (air knife, etc.). It has been demonstrated that airborne impurities can dissolve into standing DI water droplets remaining on the surface of a cleaned assembly. This can result in otherwise unexplainable "water stains" that form when the water ultimately evaporates and deposits the previously airborne materials. This is likely a second order issue, but if the assembly facility is in a heavily industrialized/polluted area, and the air quality in the assembly area is not cleaned up in any way, this can be an issue. Best regards, Leo Director of Applications Engineering ASAT, Inc. 3755 Capital of Texas Highway, Suite 100 Austin, Texas 78704 ph 512-383-4593 fx 512-383-1590 [log in to unmask] www.asat.com The information contained in this electronic message is CUSTOMER/SUPPLIER PRIVILEGED AND CONFIDENTIAL INFORMATION intended only for the use of the individual or entity named above. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution and copying of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender by electronic mail. Thank you. -----Original Message----- From: Brian Ellis [mailto:[log in to unmask]] Sent: Thursday, March 17, 2005 11:35 AM To: [log in to unmask] Subject: Re: [TN] DI Water ... and one of the most important factors, far more than the water quality, is how you dry. If you have comparatively dirty water that is mechanically removed, you may get far less residual contamination than with excellent water which is contaminated with residues from under the components and simply allowed to evaporate. Been there, done that. Brian Douglas O. Pauls wrote: > I would agree with Joe. I would use at least 2 megohm-cm (0.5 uS/cm) > resistivity water. I would not go higher than 10 megohm-cm because the > water starts to get too "hungry" can can start to attack stainless steel. > > I do not know of any IPC specifications on water quality, but we will be > starting on revisions to the J-STD-001 Handbook and perhaps we can fold > that in. Keep in mind that cleaning is a solubility equation. It is not > just water quality that is important but temperatures, pressure, flow > rates, etc. > > Doug Pauls > > > > > Joe Russeau > <jrusseau@PRECISI > ONANALYSTS.COM> To > Sent by: TechNet [log in to unmask] > <[log in to unmask]> cc > > Subject > 03/17/2005 09:39 Re: [TN] DI Water > AM > > > Please respond to > TechNet E-Mail > Forum > <[log in to unmask]> > ; Please respond > to > Joe Russeau > <jrusseau@PRECISI > ONANALYSTS.COM> > > > > > > > Hello, > > Obviously the higher the resistivity of the DI water the more effective the > cleaning. Using water in the 2-10 Megohm-cm range is usually sufficient > for > water purity. We usually recommend leaning towards the higher end of that > range for better cleaning, but it depends on your water system and set-up > as > to the level of quality that can be reached. > > As far as specs, I am not aware of any industry specs or guidelines for DI > water quality, but that does not mean that none exist. Some of the other > Tech guru's may have more information on that front. > > Best Regards, > > Joe Russeau > Process Analyst > > Precision Analytical Laboratory > > > > ----- Original Message ----- > From: "SUBSCRIBE TechNet Doug" <[log in to unmask]> > To: <[log in to unmask]> > Sent: Thursday, March 17, 2005 9:26 AM > Subject: [TN] DI Water > > > >>How "clean" does my DI water need to be for cleaning water soluble flux >>from PWB assemblies? Is there an industry minimum guideline? >> >>--------------------------------------------------- >>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 > >>----------------------------------------------------- >> > > > --------------------------------------------------- > 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 > ----------------------------------------------------- > > --------------------------------------------------- > 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 > ----------------------------------------------------- > --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------