Good Morning, I need to ask some more questions on this thread. One of the reasons our customer went to a water soluble paste was the high voltage/damp heat test requirement on the finished assembly. The test requirement is 1000 hours of damp heat test at 85C/85RH. The voltage requirement is 250 volts. BGA pad spacing is .050. The customer was concerned about passing this test. Regards Steve Kelly Steve Kelly PFC Flexible Circuits Limited PH: (416) 750-8433 Fax: (416) 750-0016 Cell: (416) 577-8433 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Kelly Sent: Monday, April 14, 2008 1:58 PM To: [log in to unmask] Subject: Re: [TN] Possible flux contamination issue Thanks everyone for the help. Regards Steve Kelly -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis Sent: April-11-08 11:50 AM To: [log in to unmask] Subject: Re: [TN] Possible flux contamination issue 24 years ago (yes 24!), I gave a paper at InterNepcon, in Brighton, UK, entitled "Contamination on Components and Small Assemblies". I no longer have a copy, but I'm fairly sure I evoked the need to have all the components supplied clean to avoid just this kind of problem. Brian Steve Kelly wrote: > Good Morning, > > We are assembling a BGA connector onto a flex circuit. The BGA has leaded > balls and the BGA manufacturer uses a no-clean process to attach the balls > to the connector and does not clean afterwards. > > When we assemble the BGA connector to the flex we use water soluble paste > and then we clean. After damp heat cycling we have seen some shorts. When we > take off the connector we see flux residues on the underside of the > connector but not on the flex. So my question is - what are the concerns > about mixing no-clean and water soluble? Is the failure likely due to > inadequate cleaning or is there something else I should be concerned about. > I realize this is probably not the way it should be done but some days you > just do what the customer wants - good or bad. Thanks in advance. Steve > Kelly > > > > Steve Kelly > > (416) 750-8433 (work) > > (416) 750-0016 (fax) > > (416) 577-8433 (cell) > > > > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > 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 15.0 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 15.0 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 15.0 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 -----------------------------------------------------