Graham, I am familiar with the "dishwasher" machine that you have described. My curiosity is about the dishwasher machine where you use 75% isopropyl alcohol and 25% water. Was this dishwasher specially made for this solution? The reason I ask is due to the explosive nature of IPA. Normally anything to do with IPA requires explosion proof motors and accessories. Could you please comment? (cud u pls com?, I couldn't resist) Thanks, Bill Kasprzak Moog Inc. Manufacturing Engineering, Electronics > -----Original Message----- > From: Graham Naisbitt [SMTP:[log in to unmask]] > Sent: Tuesday, April 22, 2003 6:47 AM > To: [log in to unmask] > Subject: Re: [TN] Cleaning Question - Rinse water resistivity? > > > We have set up our Emulsonators with wash time of 30 minutes and > > rinse time of 15, but the rinse cycle will continue for up to 30 > > minutes if wash sump resistivity does not reach at least 1 > > megohm-centimeter. If this level is not met within 30 minutes, the > > cycle will abort. > > > > FYI to the group, this is a batch "dishwasher" style machine, with > > counter-rotating spray arms at top and bottom, and separate wash > > and rinse tanks. The wash tank contains water with 5 or 10% of wash > > chemistry, in our case Bioact EC-7R. Bioact is not miscible, and > > separates, but pumping action creates an emulsion that is pretty > > effective at removing RMA flux. > > > > After the wash cycle, the emulsion drains back into the wash tank, > > the valves close, and DI water is pumped into the cleaning chamber > > from a separate tank and recirculating loop. In this loop, rinse > > water drains from the wash chamber into a decanter, where Bioact > > floats to the top, and the water returns to the rinse tank. Rinse > > tank water is pumped through a particle filter, carbon, and > > mixed-bed before it flows into the wash chamber. > > > > Since water does not mix with Bioact, the rinse operation uses > > water to mechanically remove the solvent, basically "pushing" > > the Bioact residue off of the board surfaces. Any solvent left > > on the board will include flux and ionic residues dissolved within. > > In our process, boards come out with no visible flux residue, but > > we use these systems for gross flux removal, not final ionic > > cleanliness. Before conformal coat, we clean with a separate > > dishwasher containing 75% IPA and 25% DI water. > > > > Joseph > > So before you coat - and seal in anything nasty - how do you determine if > the end product will be reliable? > > Do you do any ROSE / SEC testing? If so, what level do work to? > > -- > Regards Graham Naisbitt > > [log in to unmask] > > Cell: +44 79 6858 2121 > > Concoat Limited - Engineering Reliability in Electronics > > --------------------------------------------------- > Technet Mail List provided as a free 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/html/forum.htm for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 > ext.5315 > ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------