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Cleaning no-clean residue

Steve B

#5970

Cleaning no-clean residue | 16 April, 2001

Does anyone know of a reason, other than visual, contact, or testability, for cleaning a no-clean residue off a board? Are there any SIR or long term reliability advantages to cleaning a no-clean residue?

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#5972

Cleaning no-clean residue | 16 April, 2001

Two off the top of my head are:

1 Fluxing / soldering process is either not in-control or not capable.

2 Ionic materials on the board board or components compromise the LT reliability of the product.

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Steve

#5986

Cleaning no-clean residue | 17 April, 2001

I have struggled with this myself. Usually where the pressure to clean the residue off is from the people who see the residue but do not understand the characteristics.

I have not found a reason to clean residue off. A few people from our design group hold the stance that the residue is bad, but we have yet to prove it.

Resist the pressure to clean the boards until you have good data. Opinions don't prove anything.

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#5987

Cleaning no-clean residue | 17 April, 2001

Continuing with Steve's comments, the true measure of whether or not residues [NC or not] are good or bad is found in the results of an laboratory analysis of the residues and an assessment of the impact of that level of residue.

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Brian W.

#5990

Cleaning no-clean residue | 17 April, 2001

I have only found one reason to clean the residue. On some high power/high impedance or RF circuitry, that little bit of residue caused electrical performance problems. Other than that, most people who want it cleaned are having it done for visual effect. One customer sold boards as spares, and they felt that most people would not understand is they opened their box and found "gunk" on the board.

Brian

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#6001

Cleaning no-clean residue | 18 April, 2001

An interesting explanation [from a design engineer perspective] of "skin effect" in RF circuits can be found at http://www.ednmag.com/ednmag/reg/2001/04122001/08john.htm

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