Flux residue effects on circuit performance?

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Can anybody explain breifly what some of the effects of flux... - Apr 15, 2002 by

Points are: * Seminal study is: "Evaluation of Low Residue ... - Apr 15, 2002 by davef

Dear Tom : I hope I �m not too late. We produce PC mother... - Apr 28, 2002 by Hany A. Salam

You can try using the brand-solvent "Genesolv 2004" in conju... - Apr 29, 2002 by ianchan

Tom Van Heuklon

#19508

Flux residue effects on circuit performance? | 15 April, 2002

Can anybody explain breifly what some of the effects of flux residue from a no clean process might be on circuit performance? Alternatively, might you tell me where I might find such information?

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davef

#19514

Flux residue effects on circuit performance? | 15 April, 2002

Points are: * Seminal study is: "Evaluation of Low Residue Soldering for Military and Commercial Applications: A Report from the Low Residue Soldering Task Force," published by Sandia National Labs in June 1995. Look here http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=7878 for contact information. * This leads on the boarder point. Search the fine SMTnet Archives to get started. Probably 50+% of our discussion here on SMTnet relates to NC flux. As an example, a recent thread ( http://www.smtnet.com/Forums/Index.cfm?CFApp=1&Message_ID=19507 ) laments on the difficulty of using NC flux in RF circuits. * Other areas of concern about circuit performance are: conformal coating, flip chip under-fill, proper process control so to not over apply flux, customer acceptance, tougher soldering process control, and ladeda.

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Hany A. Salam

#19705

Flux residue effects on circuit performance? | 28 April, 2002

Dear Tom :

I hope I �m not too late. We produce PC motherboards with some buses exceeding the speed of 100MHz . we use no clean flux and it is OK even with the residues you can see under a microscope. But according to our own experience through a modification for more than 1000 boards, the flux residues remaining after manual rework are very critical. Tens of faulty boards passed all normal & burn-in tests just by cleaning the residues of the No Clean Flux.

According to what I understand, N.C.F. means it is not harmful to your components & PCB material from the chemical point of view (corrosion for example). But it could be problematic such as in our case.

Regards.

Hany

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ianchan

#19713

Flux residue effects on circuit performance? | 29 April, 2002

You can try using the brand-solvent "Genesolv 2004" in conjunction with a degreaser machine(source for own machine type?).

this all helps to clean off the NC flux. we used it all integrated together, to clean a satellite modular card.

reason we had to use NC flux, is coz the base PCB materials metallized pads oxidized after WS cleaning processes.

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