Raghav Nothing you have said convinces me, yet, that you have to clean the boards. If you use a modern "no-clean" flux, this will save you having to do a meticulous, costly and dangerous operation and will leave very little residue on the boards and what there is will be hardly visible. Using IPA alone is not effective and the boards will almost certainly be less reliable than with using a good "no-clean" process. The "white residues" you are seeing are almost sure to be ionic or partly so, because they will contain metallic salts. In addition, IPA is a distinct fire hazard unless operated in an inert atmosphere (flash point less than room temperature) and is somewhat toxic (can be absorbed through the skin). If I were you, I would scrap your current process as soon as possible and run qualification tests on selecting a "no-clean" flux from the many available. If, for any good reason (and I don't really consider that there is a good cosmetic one), you cannot use "no-clean", then select a good water-soluble flux, again from the many available, and clean with water. However, be warned: water-cleaning MUST be done well and proper qualification of the process is essential. For further reading: http://www.protonique.com/plcom/files/whycl.htm and http://www.protonique.com/unepstoc/report/STOC1998ch2.pdf (you may find other useful references on http://www.protonique.com/unepstoc which is the official site of the UNEP solvents committee). Am I correct in thinking you are in Bangalore? If so, I have a colleague who is a consultant in cleaning technology, stationed in Hyderabad. He is not specifically into defluxing, although he is quite knowledgeable in this sub-sector. You may find it more economical to use his services, rather than do it all yourself. Brian PS. I would prefer it if you spelt my name right!! Raghavendra Bs wrote: > Hello Brain, > > Sorry could not complete the mail. > > Now we are facing the cleaning problem in the boards which are processed in > wave soldering. After wave soldering process, we are cleaning the flux > residues and this process is taking more time to effectively clean the > boards with IPA (more time consumed to clean the white patches formed due to > IPA, which is not good in cosmetic). The PCBA is a communication purpose > boards (Class B according to IPC). Now we need to try out any other solution > which is effective in cleaning and should not be harmful for the board. If > any other information is required, please let me know. > > Thanks in advance > > Raghav > > -----Original Message----- > From: Raghavendra Bs > Sent: Sunday, October 27, 2002 2:23 PM > To: 'Brian Ellis'; TechNet E-Mail Forum. > Subject: RE: [TN] TechNet > > Thanks for the reply Brain, > > -----Original Message----- > From: Brian Ellis [mailto:[log in to unmask]] > Sent: Sunday, October 27, 2002 12:15 PM > To: TechNet E-Mail Forum.; Raghavendra Bs > Subject: Re: [TN] TechNet > > Raghav > > IPA is not a good solvent for most types of flux residue, because it > will not dissolve many components. Tell us more about what you are doing > (soldering methods and parameters, flux type, type of end product, > degree of reliability needed, conditions of use of end product and so > on) and we shall be able to help you better. > > Brian > > Raghavendra Bs wrote: > >>Hi, >> >>Can any one give some hints on Cleaning of wave soldered PCB's, to remove >>flux residues on the board. In IPA, white stains are left on the board and >>cosmetically does not look good. Is there any other solution. >> >>Regards >>Raghav >> >>--------------------------------------------------- >>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 > ----------------------------------------------------- > > > --------------------------------------------------- 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 -----------------------------------------------------