> I have a question regarding a test for flux contamination on conformally > coated boards. > > I know all about testing uncoated boards but was wondering if there are any > tests for type UR coated boards? > > Does a temperature soak do any good at bringing problems to the surface? > > Does baking cause any remaining flux to become conductive? > > Does a humidity/temperature soak do any good? > > What were looking for is a parallel electrical path that might reduce the > value of a small SMT resistor. > > Thanks in advance, > > KennyB Kenny I would assume that you have completed assemblies? If so, then I would also presume that you have previously run some sort of accelerated life testing with heat and humidity. If so, then repeat that test to see if you register any failures. Do this powered-up. If you have the chance, get some test coupons prepared that will allow over mounting of components, and run process characterisation SIR tests. This will measure the compatibility of your manufacturing process from the stand-point of electro-chemical compatibility. I have a draft spec that I can send you if you wish - please confirm. One final pointer is that relating to adhesion of the coating. Does it stick to component legs? Y/N Does it stick to component bodies? Y/N Does it stick to bare copper or tin/lead? Y/N Does it stick to the substrate? Y/N To my knowledge coatings are not intelligent - so cannot tell the difference between these surfaces, so if it not sticking well to the substrate, then there must be something else present that is preventing it from doing so. This could be flux residues or some other "contaminant". Will this affect circuit performance.....that's when you need to test......around and around we go!! -- Regards, Graham Naisbitt [log in to unmask] Mobile: +44 (0)79 6858 2121 NEW: Tech-Shot 05 :NEW NEW: SoldaPro Wizard :NEW Sales: Concoat Limited Millfield House, Fleet Road Fleet GU51 3QF - UK Phone: +44 (0)1252 813706 Fax: +44 (0)1252 813709 Works: Concoat Limited Alasan House, Albany Park Canberley GU16 7PH - UK Phone: +44 (0)1276 691100 Fax: +44 (0)1276 691227 --------------------------------------------------- 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 -----------------------------------------------------