Water Soluble vs. No Clean

Just a few problems you might have to deal with:

1) Your bare boards must be clean and kept clean though-out the process. You could notice handling contamination that might otherwise have been removed in your wash.

2) You will see solder balls and beads that you never noticed were there with water soluable.

3) Tighter control of print process is needed to cut back on solder balls and beads.

4) Placements of parts must be very good as off-center placemtents can contribute to solder beads.

5) Re-work on the SMT line can be a bit more time consuming as post re-work clean-up is more difficult.

6) Re-cutting of stencils might be required on some builds as smaller apertures or home-plate apertures might be needed to cut back on SMT solder issues.

7) You will need to buy additive for your stencil cleaner.

Sounds like a lot but overall, pretty simple stuff to deal with and most of these result in positive quality changes.

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We manufacturer cleaning equipment (full disclosure) so, our answer may seem self-serving. The facts however are accurate and relevant so here I go�

Changing from an OA (water soluble) flux to a no-clean flux makes sense. After all, even die-hard cleaning proponents like me can concede the fact that not all assemblies have to be cleaned. Please note the fact that I did not say �not all assemblies would benefit from cleaning�. To be clear, all assemblies benefit from cleaning although the benefits of cleaning may not be fully appreciated on all boards. Matters of use that affect liability, dependability etc all play a role in the decision to clean or not to clean. Obviously, boards and applications benefit from cleaning. Most medical, military, flight, space, and other high reliability applications normally require cleaning for a reason.

Can YOU give up cleaning? Maybe, but you need to consider the other costs of not cleaning.

There are a number of articles available that demonstrate the cost of not cleaning. I am pleased to provide links to such articles:

From Austin American Technology: http://www.aat-corp.com/whynocleans.pdf

From Aqueous Technologies http://smt.pennnet.com/articles/article_display.cfm?Section=ARCHI&C=Colum&ARTICLE_ID=245681&KEYWORDS=konrad&p=35

From Zestron http://smt.pennnet.com/Articles/Article_Display.cfm?Section=ARTCL&ARTICLE_ID=249818&VERSION_NUM=2&p=35

From Forsite http://www.residues.com/pdfs/Circuitnet/Process_Residues_Cause_Field_Performance_Problems.pdf

http://www.residues.com/pdf/FailureOfACircuit.pdf

I hope this helps.

Mike Konrad Aqueous Technologies (909) 944-7771 ext 29 www.aqueoustech.com konrad@aqueoustech.com

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We run both No-Clean and Water Soluble boards without any problems. We had problems with solderballs, but adjusted the P&P machines not to push the parts into the paste so much. Home plate apperatures help also. The biggest question is if your customer will be happy with flux on your boards.

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