For me, the important things are a) there must be no water puddling between the components (i.e., instantaneous draining; if it occurs, it will dissipate the kinetic energy of the jets before the water can do any work under the components b) the jets should impinge at an acute angle to the plane of the board, to ensure there is max ingress under the components c) the angle of impingement must vary d) there must be no shadowing e) the wash must have solid jets and the rinses very fine sprays (water droplet diameter < smallest under-component space) f) the pressure is relatively unimportant: it is the energy imparted to the water that counts. As a rule of thumb, you need ~2 kW of pump for every metre of wash bar. Too high a pressure can even be negative because the water tends to bounce off the surfaces. This is the voice of experience as an ex-maker of aqueous machines. See my book for more details. g) the number of rinses should be sufficient to ensure several replacements of water under the tightest component. h) high speed (>200 km/h) air knives form an essential part of the cleaning process, also impinging at an acute angle, to blast residually contaminated water from under the components. Brian John Parsons wrote: > We are looking at adding to our current batch washer (Older Aqueous Tech > unit) and I am interested in hearing some thoughts as well as first hand > experience on how the following two cleaning systems work with regards > to low profile (BGA's etc.) devices run as both conventional and > lead-free processes. We are currently running water soluble flux and > are not using saponifiers for the cleaning process. I have listed the > two machines we are considering along with my thoughts. I am interested > in hearing yours. > > > > Aqueous SMT1000 > > - dish washer style loading, poor loading = poor cleaning > > - vertical loading improves throughput > > - high pressure pumps 120psi wash, 45psi rinse for leadfree but > can this style of machine effectively clean under BGA devices? > > > > Electrovert Aquajet > > - large cleaning area (30x30") but horizontal loading would > appear to limit throughput. > > - Is any racking available for this machine to process boards > vertically for increased throughput (within height limitations of front > opening) or does design technology reduce cleaning cycle when compared > to Aqueous machine thereby somewhat offsetting loading capacity. > > - wash and rinse technology coupled with horizontal loading > seems that it would do a significantly better job on cleaning under low > profile devices > > Regards, > John Parsons > > > > > --------------------------------------------------- > 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 847-509-9700 ext.5315 > ----------------------------------------------------- > > --------------------------------------------------- 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 847-509-9700 ext.5315 -----------------------------------------------------